Thursday, April 30, 2009

Temperature Settings and Set Points for Tankless Heaters

Setting the Temperature on a Bosch tankless water heater can be confusing. One would think that to get hotter water and thus have a better shower that increasing the set point or temperature setting on a water heater would be the best idea. BUT on a tankless heater this may not be the case. In most cases we want the set point temperature to be just above the useable water temperature for the household and this would be around 110 F.

If the Tankless heater is set for 125 F like most tank heaters, then the outlet temperature at the shower end will have to be adjusted or mixed with cold water to make a comfortable shower.

When the water is mixed the amount of water forced through the tankless heater is reduced, and if too much cold water is needed to temper the hot water then the flow rated though the heater may be reduced to below the minimum and the tankless heater will shut off. By setting the temperature closer to the useable temperature, there is more flow through the hot side of the system (through the heater) and thus keeps up any minimum flow requirements.

Tank heaters need higher settings so that the hot water in the tank "lasts longer" due to the mixing of cold water and to prevent bacteria from growing in the "stored" water.

Just because one sets a tankless heater to 125 or higher, the heater may not have the capability to reach that temperature due to heat input, flow rate or inlet water temperature. Every tankless heater has a maximum rise temperature based on the flow rate through the heater. The temperature setting will not increase this fact (as it it physics) and thus the temperature setting becomes a maximum setting or high limit. For example the Bosch 2400ES gas heater can heat a flow rate of 6.2 gpm 45 degrees F. If the inlet is 60 then the outlet would be 105 F no matter what the set point of the heater is above 105F.

Tuesday, April 21, 2009

Z-Flex Z-Vent Stainless Steel Venting Adaptors

GlobalTowne stocks Z-Flex Z-Vent Stainless Steel Venting Adaptors that allow you to connect your tankless water heater or boiler to Z-Flex Z-Vent Stainless Steel Vent Pipe.

The Z-Flex Appliance Adaptors PDF file lists each Z-Flex Appliance Adaptor for tankless water heaters, boilers, gas booster heaters, pool heaters, etc sorted by manufacturer and model number.

We stock the following Z-Flex adaptors:


Z-Flex Z-Vent Stainless Steel Venting

GlobalTowne is an Authorized Distributor of Z-Flex Z-Vent Stainless Steel Venting.

The Bosch AquaStar 2700ES / Bosch AquaStar 2400ES / Bosch AquaStar 2400E / Bosch 250SX requires 3" or 4" stainless steel venting for Category III Gas Appliances. Our Z-Flex Z-Vent venting meets these requirements and is rated AL29-4C.

Z-Flex Z-Vent is approved for Category I (vertical only), II, III & IV applications and is designed for use with boilers, high efficiency gas and oil heaters and water heaters where cool flue gases are vented under pressure. Z-Vent contains a built-in, fail-safe gasket and locking band connection. No sealant is required.

Z-Flex Z-Vent comes in 3" diameter vent pipe all the way up to 24" diameter vent pipe.

We stock the following:
We can special order the 5" diameter through 24" diameter vent pipe and have it shipped directly from the factory in New Hampshire -- Same Day Shipping!

Z-Vent is manufactured using AL29-4C advanced ferritic stainless steel** with unmatched corrosion resistance for use with condensing furnaces and boilers. Z-Vent was developed in the early 1980s and has thousands of field installations to date. Z-Vent is now manufactured utilizing a fail-safe gasket connection. No sealant required.

The lengths of pipe may be cut on non-expanded end using aviation snips or a hacksaw (24tpi). The cut end must be filed or sanded smooth before joining.

Call us at 888.726.9752 to help you select the stainless steel venting parts or just to verify your venting run.


Sunday, April 19, 2009

About Bosch Thermotechnology Corp

Bosch Thermotechnology Corp. is the US operation of the Bosch group’s heating and hot water division. Bosch is an industry leader in heating and hot water heating products with an estimated turnover of approximately $2.5 B USD and over 12,900 employees across 9 countries worldwide.

Bosch Thermotechnology Corp. offers a broad range of products for both domestic and commercial heating and hot water heating that in the US includes two well known and reputable brands – Bosch and Buderus. The Bosch Thermotechnology Corp. brands are working separately and collaboratively to produce quality, highly efficient and durable products to provide heating and water heating solutions to the US.

To find out more, please visit the web site:

For Bosch Consumer Retail Product Information:

Bosch Tankless Water Heaters
Bosch tankless water heaters are the only tankless water heaters in the U.S. that have been specifically designed for the U.S. market.

Trusted Brand in American Homes
Bosch water heaters' average life expectancy is more than 20 years, it saves energy of up to 50%, and supplies endless hot water.


Bosch Technical Support

If you have purchased a Bosch Tankless Water Heater and you have a question or a problem then you have no need to worry. Bosch Technical Support has technicians standing by to help.

Online technical support is the best place for installation information, technical and application bulletins, and service information on all Bosch tankless products.

Phone support is available to owners of Narural Gas (NG) or Liquid Propane (LP) Bosch tankless water heaters should call 800.624.3111.

Owners of Bosch electric tankless water heaters and mini-tank heaters should call 866.330.2729.

Bosch Technical Support is provided during normal working hours, Monday through Friday.

Whenever you contact Bosch Technical Support you will need to provide your Bosch model number and the serial number off of your unit.

Special Reminder:
Extra precautions should be taken when working with gas or electric equipment. The use of a qualified installer or service agent is recommended for any installation or service work performed.


The Bosch AquaStar Warranty

Bosch has the best warranty in the industry for its line of AquaStar Tankless Water Heaters!

Bosch provides a 12 year warranty on the heat exchangers for all gas and propance tankless water heaters (2 years for parts).

Here is the warrantly as listed on

AquaStar water heaters are warranted by the Bosch will furnish a replacement heat exchanger and will furnish a replacement of any other part which fails in normal use and service within the applicable periods specified below, in accordance with the terms of this warranty. The Bosch Water Heating replacement will be warranted for the unexpired portion of the original warranty. This warranty will be valid only for water heaters in possession of the original purchaser as recorded on the warranty card.

The Heat Exchanger
If the heat exchanger fails within twelve (12) years after the original installation and operation, Bosch Water Heating will furnish a replacement heat exchanger. However, if the water heater is installed in other than a single family dwelling, or is used as a circulating heater in any application, this heat exchanger warranty is limited to two (2) years from date of original installation and operation.

All Other Parts
If any other part fails within two (2) years after original installation and operation, Bosch Water Heating will furnish a replacement part free of charge.

Shipping Costs
In addition to supplying the replacement part(s), Bosch Water Heating will provide ground service delivery for these parts.Expedited or upgraded shipping will be charged to the customer.

This warranty does not cover any labor costs associated with service, removal or re-installation of part(s). All such costs must be borne by the Purchaser.

This warranty will not apply:

1. to defects or malfunctions resulting from failure to properly install, operate or maintain the unit in accordance with the printed instructions provided;

2. to damage or abuse, accident, neglect or freezing and other acts of nature;

3. to damage resulting from operation with either the thermocouple or overheat sensor removed;

4. to failure of the heat exchanger resulting from the operation of the water heater in a corrosive atmosphere or at water temperatures exceeding the maximum rating, or if the water heater is not supplied with potable water.

5. to defects or damage cause by any attachment or modification, including any energy-saving device.

Note: The water heater must be free of damaging scale deposits and not subject to gas pressures greater than those shown on the rating plate, which must not be altered, defaced or removed.

It has come to our attention that products from Bosch Water Heating are being sold through on-line auctions and other unauthorized distribution channels. We believe that in some cases there are legitimate consumers trying to sell product that they have purchased through legitimate distribution channels. However, we are finding that some of the merchandise has actually been stolen from our customers. Please be advised that our product warranty is void with respect to stolen goods. Further, we reserve the right to require a legitimate sales receipt showing that the product was purchased from one of our customers in order to provide warranty coverage.

How to Make a Claim

1. The Owner should contact the dealer who sold the water heater covered by this warranty or

2. Owner should submit the warranty claim directly to Bosch Water Heating at the address listed below, and they will arrange for the handling of the claim.

3. Whenever any inquiry or service request is made, be sure to include the water heater model number, the date of manufacture, date of installation, Dealer's name and the watts and voltage.

4. When returning the water heater or component part(s), they must be individually tagged and identified with the Returned Goods Authorization # issued by Bosch Water Heating and shipped prepaid to Bosch Water Heating at the address below.

No one is authorized to make any other warranties on behalf of Bosch Water Heating. It is expressly understood that the replacement warranty of Bosch Water Heating shall be in lieu of any and all other warranties, express or implied, including warranties of merchantability or fitness for a particular use or purpose, and further that Bosch Water Heating shall not be liable for any loss or damage directly or indirectly arising from the use of the hot water heater, or for any consequential damages arising from such use (including damages from water leakage). Bosch Water Heating's sole liability with respect to any defect shall be for the replacement of defective part(s). Some states do not allow such limitations and exclusions, so the above may not apply to you. This warranty gives specific legal rights. You may also have other rights which vary from state to state. In the event that warranty service is required, reasonable proof of the effective date of installation and operation must be provided; otherwise it may not be possible to honor warranty.

Note: Specifications and product information subject to change without notice.

Wednesday, April 15, 2009

Venting the Bosch 2700ES and 2400ES Tankless Heaters

There are three venting options for the Bosch 2700ES and Bosch 2400ES tankless water heaters.

For those who want to vent out of the side wall, the AQ3ES Horizontal Vent Kit has all of the parts needed (based on the assumption that you are venting out of the same wall you have mounted the heater on).

In addition to the 90 degree elbow, wall thimble, and the intake/exhaust termination boxes, this Z-Flex 3" stainless steel vent kit comes with enough vent pipe to meet the minimum three feet requirement. The Bosch warranty requires that all exhaust systems have at least three feet of straight vent pipe.

The ES VVT Vertical Vent Kit has all of the parts needed to vent up through the roof (except for the straight pipe). You will need enough straight pipe to get you three feet above your roofline.

The ES VVT Vent Kit comes with flashing, storm collar and rain cap for the roof line as well as a fire stop support, a stick of pipe, a 90 degree elbow, a vertical drain tee and a drain tube kit.

Lastly, the AQOK Outdoor Vent Kit turns the Bosch 2700ES/2400ES heaters into Outdoor Tankless Water Heaters. The AQOK Vent Kit bolts right on top of the heater to properly channel the makeup (combustion) air and the exhaust. The AQOK also prevents rain from getting into the tankless water heater.

With three venting options, the Bosch AquaStar 2700ES and Bosch AquaStar 2400ES heaters have the most versatility on the market!


Tuesday, April 14, 2009

PowerStar Tankless Electric Water Heaters

The PowerStar Electric Tankless Water Heaters are designed for "point of use" applications, meaning sinks and other low(er) flow water applications. There are four models of these tankless heaters, the AE3.4, AE7.2, AE9.5 and AE12. The numbers designate the kw or kilowatt rating of the unit. The AE3.4 runs on 120 volts but the AE7.2, AE9.5 and AE12 need 240/220/208 volts for useable operation.

None of these heaters comes with a plug so they need to be HARD WIRED back to an electrical panel due to their amperage requirements. A standard circuit within a home is 15 amps for a 120 volt circuit. The AE3.4 requires 30 amps, so it can not be "plugged in". The AE3.4 can only really be used in warm weather climates where the inlet water is at least 65 or warmer. The AE3.4 will raise the water temperature flowing through the heater 20 degrees at a flow rate of 1 gpm. So, if you are starting with 70 degrees the outlet temperature will be 90. If the flow rate is .5 gpm, then the outlet temperature change will be 40 degrees.

The Powerstar AE7.2 is also a 30 amp unit but utilizes 240 volts thus it has twice the power of the AE3.4. At a flow rate of 1 gpm, the unit will provide about a 45 degree change in the water temperature. This unit may still not be "big" enough for cold weather climates if the inlet temperatures are 50 thus the outlet temperature would be 90. This is good for washing hands but not much else. Please note that the AE3.4, AE7.2 and AE9.5 do NOT have a knob or dial to control outlet temperature. The AE12 does have a temperature control though.

The Powerstar AE9.5 is also a 240/220/208 unit and will provide about a 60 degree change at a 1 gpm flow rate and the heater requires 40 amps to operate. This unit is usually the best fit for most point of use applications.

The Powerstar AE12 Power Stream tankless heater is the "largest" in terms of KW in the family. Please note that all the heaters are identical in physical size. The AE12 can provide a temperature change of 40 degrees at 2 gpm and a 65-70 degree change at 1 gpm. This unit can possibly be used with low flow showers in a warmer weather location.

When dealing with electrical tankless heaters, the input voltage is very important. The heaters are rated based on a full 240 volts. If the input voltage is less than 240 then the wattage will be reduced thus the output temperatures will be reduced. This is NOT a linear function. For example, if the voltage is cut in half, then the wattage will be 1/4 of the rated kw and the performance will be reduced by 4 times. It is important to have an electrician measure your actual voltage and to review your panel capacity when installing any Electric Tankless Heater including the Power Stream Point of Use heaters.


Sunday, April 12, 2009

Bosch AquaStar 1600H versus 1600P

Bosch currently has two 1600 series tankless water heaters in the lineup: the Bosch AquaStar 1600H and the Bosch AquaStar 1600P.

Both of these Bosch tankless water heaters deliver 4.3 GPM at a 45 degree F temperature rise. They both have a gas control that modulates the burner input in response to flow. The BTU input on both water heaters is between 30,735 and 117,000 BTU input.

They both are designed to be vented vertically using 5" diameter Type B Galvanized venting. Globaltowne sells the H/P VVT Vertical Vent Kit to help with this vertical venting. Alternatively, both can be vented through the side wall with the AQ4 Power Vent.

The main difference between the 1600H and the 1600P is the ignition system. The Bosch AquaStar 1600H uses Bosch's patented Hydro Ignition system. This iginition system has no pilot light and no electrical requirement. The Bosch 1600H comes in two models:

The Bosch 1600P has a standing pilot light for its ignition system. The Bosch 1600P also comes in two models:
Although the Bosch 1600H costs more than the 1600P, the 1600H should save you a lot of money over its lifetime as it is not constantly burning gas for a pilot light. Some customers, however, prefer the lower cost of the 1600P. Also, some of our customers who live in very remote locations prefer the 1600P over the 1600H due to its lower mechanical complexity.
Both are very solid heaters with great reputations!


Saturday, April 11, 2009

Where is GlobalTowne Located?

People call us everyday and ask us the question "Where are you located?" The answer is we are everywhere!

Our headquarters are in Cleveland Ohio and this is our main warehouse. We also have people outside of Ohio (but still in the United States!) answering the phones to provide you with 24 x 7 phone coverage.

More importantly, Globaltowne has a warehouse in Las Vegas, Nevada to serve the west coast and a warehouse in New Castle, Delaware to serve the east coast and New England. With three warehouses across the US we are able to quickly get you your new Bosch Tankless Water Heater.

GlobaTowne ships daily to all 50 States and all Canadian Provinces.


Special Bosch Promotional Code Coupon

GlobalTowne is offering a special Promotional Code for 5% off of all Bosch Tankless Water Heaters and accessories!

When buying online at you can enter TANKLESSBLOG at the Promotional Code prompt during the Checkout process. The Bosch Discount Coupon will instantly take 5% off of all Bosch Tankless Water Heaters and accessories, such as venting.

The TANKLESSBLOG Promotional Coupon is good through the end of November 2010. If you are not comfortable placing your order online, simply call 888.726.9752 and mention the TANKLESSBLOG Special Code and you can still get this extra savings!

Whenever you use a Promotion Code at, you always get the lower cost of the coupon or any existing promotional sale. Promotional Codes cannot be combined.


Wednesday, April 8, 2009

ARISTON Mini-Tank Heaters

The ARISTON GL heaters are NOT tankless water heaters.

The GL2.5, GL4.0 and GL6+ heaters are small tank heaters with the numbers in their part number signifing their capacity in gallons. This is not a GPM rating. All three heaters use a 120 volt 1500 watt electric element to heat the water. Thus all the heaters will draw about 12.5 amps. All the heaters come with about a 3 foot long cord and plug. Globaltowne does sell a GFCI extension cord for use with the GL series if the 3 feet is not long enough.

The GL series is excellent for stand alone sinks. Also it can be used inline with a tankless heater or tank heater to provide instant hot water at a shower while waiting for the hot water to "arrive" from the main heater.


Monday, April 6, 2009

Whole House Electric Tankless Water Heaters

Bosch offers two Whole House Electric Tankless Water Heaters: the PowerStar AE125 and the PowerStar AE115.

A perfect alternative to the electric tank water heater, the PowerStar electric tankless water heaters are designed to replace a 40-gallon tank and provide endless hot water throughout the home.

These compact water heaters (15.5" x 15.25" x 4.5") will fit just about anywhere and are built to last!

The AE125 provides 4 GPM at a 45 degree F temperature rise. It is a single phase 27kW heater running on 240 volts. It requires 3 x 40 AMP breakers and Bosch recommends a minimum 200 AMP service to your house.

The AE115 provides 2.6 GPM at the same 45 degree F temperature rise. It is a single phase 17kW heater running on 240 volts. It requires 2 x 40 AMP breakers and Bosch recommends a minimum 150 AMP service to your house.

Bosch has provided the following map as a guideline to where the AE115 should be installed:

AE125 and AE115 Map
When the AE125 is installed in Canada the AE Canada Kit is needed. The AE Canada Kit for the PowerStar AE125 is a 6 way terminal block for use when installing the AE125 in Canada. In Canada, the AE125 requires a 120A 240V AC single phase supply protected by a 120A double pole circuit breaker.


Sunday, April 5, 2009

Bosch Outdoor Tankless Water Heaters

Bosch offers four outdoor tankless water heaters that are approved for areas where it does not regularly freeze. The heaters are equipped with electric freeze protection down to 5 degrees F above zero and are capable of withstanding an occasional overnight freeze.

The following Bosch outdoor tankless water heaters come with this freeze protection:

Bosch AquaStar 2700ES-LP / Bosch AquaStar 2700ES-NG
Bosch AquaStar 2400ES-LP
/ Bosch AquaStar 2400ES-NG
Bosch AquaStar 125BO -LP / Bosch AquaStar 125BO-NG
Bosch GWH 425HNO-L / Bosch GWH 425HNO-N

LP stands for Liquid Propane and NG stands for Natural Gas.

In order for the Bosch 2700ES and 2400ES heaters to be installed outdoors they must have the Bosch AQOK outdoor vent kit. This optional vent kit attaches to the top of the heater and prevents water from getting into the heater.

The Bosch 125BO and the GWH 425 HNO do not need any additional accessories in order to be installed outdoors. Please note that while the Bosch 125BO and the GWH 425 HNO outdoor tankless water heaters come with 110 Volt plugs, these heaters do not have to be plugged in unless you desire the freeze protection. The Bosch 125BO has a pilot light and the GWH 425HNO uses Bosch's patented Hydro Ignition system.

Bosch has approved these four outdoor heaters for the following areas of the United States:

Florida, Georgia, North Carolina, South Carolina, Alabama, Mississippi, Arkansas, Texas, Virginia (only in zip codes beginning with the first three digits 233-237), Arizona (in zip codes beginning with the first three digits 850-857 and 864), Oregon (in zip codes beginning with the first three digits 970-975), Washington (in zip codes beginning with the first three digits 980-986), California (except in zip codes beginning with the first three digits 935 or 961).

Some people install these outdoor tankless water heaters for their summer homes or cabins in areas of the US and Canada that do freeze. When these heaters are installed in freezing locations the water heaters must be completely drained so that the heat exchanger and pipes do not burst. The Bosch warranty does not cover damage due to freezing.

The WebStone Isolation Valve Kits really make the task of draining these outdoor tankless water heaters easy, so they are especially recommended for this application.

There are two big advantages to going with an outdoor tankless water heater:
  1. The water heater does not take up any space inside of your home; and

  2. There is no venting required, thus reducing both parts and installation costs.
One possible disadvantage, however, is that you may have to pay an extra installation cost to get the gas line and water lines run to your installation point outdoors.


Saturday, April 4, 2009

Bosch 2700ES / 2400ES Condensation and Rain Strategies

The Bosch 2700ES / 2400ES tankless water heaters do NOT come with built-in condensation drains.

The Bosch 2700ES / 2400ES Installation Manuals states that the Bosch 2700ES / 2400ES tankless water heaters requires the installation of an external condensate drain for:
  • ALL vertically terminating vent installations;
  • All Horizontal terminating vent installations where the total vent length is greater than 10 feet; or
  • Vent installations where any section of the exhaust vent pipe passes through an unconditioned space

Bosch recommends to install the condensate drain as close to the heater as possible.

There are three 3" Z-Flex Z-Vent condensation drain parts that you can choose from:

Each of these will require a Condensate Drain Kit (2SVEDTK24).

The 3" Vertical Condensation Drain Tee (2SVEVWCF03) acts as a 90 degree elbow and is the best choice for catching condensation and rain as it has a large reservoir.

Not all horizontal installations have an opportunity to use the 3" Vertical Condensation Drain Tee and they should therefore use the 3" Horizontal Condensation Drain Pipe (2SVEDWCF03) to replace a straight section of pipe.

The 3" Vertical Condensation Drainpipe (2SVEVDP03) has the least capacity for removing condensation and rain. It should be used as a last resort and only when 3" venting goes literally straight up from the heater. It is preferable to offset the Bosch 2400E from the vertical vent pipe and use the 3" Vertical Condensation Drain Tee (as a 90 degree elbow) along with an actual 90 degree elbow.

If you must go straight up from the Bosch 2700ES / 2400ES / 2400E heaters, we recommend that you use the 3" to 4" Increaser (2SVSI0304) and then run 4" Z-Flex Z-Vent venting. This will allow you to use the larger 4" Vertical Condensation Drainpipe (2SVEVDP04). This 4" drainpipe has a much higher capacity for removing condensation and rain than does the 3" drainpipe.


Z-Flex Z-Vent Stainless Steel Venting Tips

We stock a HUGE supply of both 3" and 4" Z-Flex Z-Vent Stainless Steel Venting. And, we now carry 5" Stainless Steel Venting! Why Z-Flex products? Simply because they are the best!

Our 3" Z-Flex Z-Vent stainless steel vent pipe mates up directly with the following Bosch Vent Kits:
Bosch requires that either 3" or 4" stainless steel vent pipe (AL29-4C) be used when installing the Bosch AquaStar 2700ES / 2400ES / 2400E / 250SX / GWH 635 ES / GWH 715 ES model heaters. The GWH 345 ESR and GWH 450 ESR heaters require 3" stainless steel vent pipe (AL29-4C).

Using other types of venting with the Bosch 2700ES / 2400ES / 2400E tankless water heaters will void your warranty and put your family's health in serious danger. Many of our Bosch 2700ES / 2400ES / 2400E tankless water heater customers ask us if they can use their existing venting. The answer is always NO. And, the Bosch 2700ES / 2400ES / 2400E tankless water heaters must have their own dedicated venting system.

Most customers use the 3" venting with the Bosch 2700ES / 2400ES / 2400E tankless water heaters. If you choose to use the 4" venting, you will need the 3" to 4" Increaser Z Flex Z Vent SS Venting (2SVSI0304).

The two main reasons to use 4" venting with the Bosch 2700ES / 2400ES / 2400E tankless water heaters is if you already have the 4" venting in place or if you intend to go literally straight up with no elbows (see comments below).

Customers installing non-Bosch tankless water heaters often require 4" stainless steel venting. Many of these customers require our 4" Universal Adaptor: Takagi, Paloma, Rheem, Noritz (2SVSNA04.5) to connect their water heater to the 4" piping system. We also carry the 3" Rheem/Paloma Adaptor (2SVPA03) for connections to certain Rheem and Paloma tankless water heaters.

Some of our customers take great care to measure exactly the distances of their pipe runs. Sometimes they have to come back to us to purchase an additional length of pipe.

Here's a tip: Buy a length of straight run pipe that is a little longer than you need. Each piece of straight run pipe can be cut with a hacksaw. You must leave at least 1.5 inches at the male end of the pipe so that it will snug up with the female gasketed end of the next piece of Z-Flex vent pipe. Any part of the male end of the pipe you cut off must be discarded as it no longer has the gasketed female end.

You do NOT need to purchase gear clamps to connect the stainless steel pipes to each other. Each female end includes a clamp and a sealed gasket to ensure a tight and snug fit. Gear clamps are only needed to secure the intake air hose to the Bosch 2400E collar and again to the intake air termination box.

We do sell the Z-Vent Sealant 3oz Tube (2SILRRTV1O6X), but sealant is NOT needed to connect one piece of Z-Vent pipe to another. The sealant is only needed to help ensure that there is a tight connection between the Top Support / Support Collar and the 3" vent pipe so that rain water does not run down the outside of the 3" vent pipe and into the flashing. Sealant is also needed in certain applications in which the normal connections cannot be made, such as when certain Z-Flex adaptors without gasketed seals are used.


Difference Between Bosch 2700ES and 2400ES Tankless Water Heaters

The Bosch AquaStar 2700ES Tankless Water Heater is a 199,000 BTU input heater that is capable of running two to three major applications at the same time. It provides 7.2 GPM at a 45 degree F temperature rise.

If you live in Florida you should be able to run three showers at the same time. If you live in New York you will only be able to run two showers and a sink at the same time.

The Bosch AquaStar 2400ES Tankless Water Heater is a 175,000 BTU input heater that is capable of running two major applications at the same time. It provides 6.2 GPM at the same 45 degree F temperature rise.

Together they are considered to be the top-of-the-line tankless water heaters on the market. They both use the same burner technology and sit in the same "World 2" chassis.

The cost difference between the two heaters is only $110. However, there may be a higher installation cost for the Bosch 2700ES heater. Since the 2700ES is capable of a higher BTU input, it may require a larger gas pipe line than the 2400ES requires. Before purchasing either the Bosch 2700ES or 2400ES tankless water heater, you should first check the gas line sizing chart in the Installation Manuals to ensure that you understand the gas line requirements.

For example, the Bosch AquaStar 2700ES-NG (Natural Gas) can only run about 15 feet on a 3/4 inch Black Iron pipe gas line. The Bosch AquaStar 2400ES-NG can run about 25 feet on a 3/4 inch Black Iron pipe gas line.

Other than the gas line requirements, the Bosch AquaStar 2700ES and Bosch AquaStar 2400ES heaters should have the same installation costs. They both require 3" Stainless Steel Venting.


2009 and 2010 Federal Tax Credit for Tankless Water Heaters

Save up to $1,500 (30% of purchase & installation) with Federal Tax Credits for Qualified Bosch Tankless Water Heaters.

Energy Efficient Bosch Water Heaters Can Save You Money On Your Taxes In Addition To Year-Round Savings on Your Energy Bill.

2009 signifies the return of a federal tax credit for non-solar tankless water heaters under the Energy Policy Act of 2005, which expired at the end of 2007. This successful program was extended under the "American Recovery and Reinvestment Act of 2009." The act re-establishes tax credits for purchasing and installing energy efficient home improvements, such as a Bosch Tankless Water Heater.

Full guidelines for the Tax Credit can be viewed on the Energy Star website. Download the Manufacturers Certification Document.

Home improvement tax credits are available for energy-saving home improvements placed in service from January 1, 2009 through December 31, 2010. Any home improvements made in 2008 are not eligible for the tax credit.

Home improvement tax credits are available for insulation, replacement windows, non-solar water heaters, and certain high efficiency heating and cooling equipment. The maximum amount that a taxpayer may claim from all of these tax credits combined is $1,500 for the two years of the tax credit (2009 and 2010) Some improvements such as geothermal heat pumps, solar water heaters, and solar panels are not subject to the $1,500 maximum.

If you are building a new home, you do not qualify for the tax credits for "eligible building envelope components" (windows, doors, insulation, roofs) or "qualified energy property" (HVAC & non-solar water heaters). However, the tax credit for photovoltaics, solar water heaters, small wind systems, and fuel cells is available for homeowners building new homes.
Internal Revenue Service (IRS) guidance for consumers can be viewed here: IRS Notice 2006-26

Tax Credit details and qualifications for Tankless Water Heaters

  • Tax Credit of 30% of the cost of the Tankless Water Heater AND Installation cost with a maximum of $1,500 (the maximum tax credit claim for energy efficient products)
  • Must have an Energy Factor of at least a 0.82 or Thermal Efficiency of 90%
  • Full Tax Credit details can be found at EnergyStar Website

Qualifying Bosch AquaStar Tankless Water Heaters: