AirGenerate AirTap Installation & Product Review

by rnaleway on March 9, 2012

AirGenerate AirTap ATI50My existing 24 year old electric water heater was on its last legs and as the single largest electric load in my house, I knew I wanted to replace it with a new, efficient model. Its location in my unfinished basement meant that I needed a new one that would not only be efficient, but also fit in a tight space without having to do much plumbing re-work. Reading up on the latest generation of heat pump water heaters led me to settle on the Air Generate 50-gallon unit because it required minimal plumbing re-work to install, had one of the highest EF ratings for an electric water heater currently available, and came with a duct connection so I could direct the cold exhaust air outside. Since it was installed last winter, I have never run out of hot water even with back-to-back showers, I have been able to turn down the hot water temperature because the tank loses very little heat compared to my old tank, and as a result our electric bills have been almost cut in half. It’s extremely quiet, has different operating modes to turn it off when I’m on vacation, and is a completely stainless steel tank so I’ll be sure it lasts for a very long time. I couldn’t be happier with my purchase, and the addition of state and federal tax credits helped to make my choice even easier.


Nicholas O’Neil, P.E., LEED® AP

{ 6 comments… read them below or add one }

Polly Ledvina August 16, 2012 at 1:13 pm

Heat pump water heaters are a great solution for foamed attics in Houston — they cool and dehumidify the space while heating water. Since we generally don’t condition these spaces directly, the heat pump water heater can suck up extra heat and humidity that might otherwise build up. No need to burn fossil fuels or expend energy on “toaster” resistance heat for water just use the waste heat you are trying to get rid of anyway.

I only wish they came in shorter models — many attics just don’t have the head-space they require. Do you have a low-boy model in the works?


rnaleway August 16, 2012 at 1:47 pm

The shortest AirGenerate AirTap Hybrid available is 58″ tall. It is the ATI50. I have not heard about a shorter model becoming available anytime soon. I believe that AirGenerate – located right in your backyard in Houston – is working on an 80 gallon AirTap that will be released this fall.

If you can place your water heater somewhere in a closet on you main floor I still have good news for you:

AirGenerate will release a so called sealed AirGenerate water heater for the US market soon. The sealed unit will have an air intake and an air exhaust duct that could be routed to and from your attic. A fan will transport the hot air via air intake duct to the water heater. The heat pump will extract the heat from the air and put it into the water. The cold exhaust air can be transported via air duct to your attic.

You are absolutely right: the water heater will heat water really cheap (since it is just transporting heat) and have the positive side effect of cooling down your hot attic space.


Charles B January 31, 2013 at 5:14 pm

Pulling hot air from the attic is an interesting idea. However, I think I want to pull air from the unconditioned garage during the winter. Perhaps the solution is an intake duct that has a controlled damper or diversion box that would enable sourcing air from the warmest location: attic or garage. I wonder what the payback time would be on the ducting and control system?


rnaleway February 20, 2013 at 12:59 am

AirGenerate is coming out with heat pump water heaters that have an air intake and air exhaust. The model numbers are ATI66-IO (in/out) and ATI80-IO (in-out). This will allow you to run a duct to the best source of air….The best air intake source could be the exterior of the home, a garage, or attic.

Home owners and contractors will not have to worry about saving money with a heat pump water heater just to pay more money on their heating bill.

The updated AirGenerate water heaters ATI66-IO and ATI80-IO are expected to be available in the US in early April, 2013.


Brandon December 11, 2013 at 7:15 pm

The area I wan to install the tank is a downstairs laundry room (where the curent electric tank is). Its a rather small closet, but has a louvered door. However, I wouldn’t want to cool the downstairs during the winter by having the outgoing air released in that space. I can have the outlet duct go through the wall to the large crawlspace. However I am concerned about the inlet pulling from the crawlspace as it stays fairly cold down there. I know the Airgenerate Spec state that it it can do fine with air at 25F degrees, but would it operate efficiently at such colder temeratures? To the contrary, if I have the inlet pull from the surrouding air (louvered door) and the outlet vent out, would I be taking any heat from that space away and thus be cooling the area?


rnaleway December 11, 2013 at 7:29 pm


I would route the cold air to the exterior of the home if you can. The AirGenerate water heaters operate in heat pump mode all the way down to 20 degrees Fahrenheit and still beat a standard electric water heater. The efficiency rating goes down the lower the ambient temperature. You will obviously get more savings during the remainder of the year.

The AirGenerate ATI66 will take air from the ambient space to power the heater. The effect is minimal though. Studies in the Northwest show a $25-$50 penalty against your heating bill when using the ambient air for water heater purposes.

If you are concerned about this you should look at getting a direct vented AirGenerate ATI66DV (also know as in and out unit). It provides an air intake duct and air exhaust duct. You could use air from your crawl space to heat the water heater. It will usually be 5-10 degrees warmer in the winter time than air coming directly from the exterior. Use the exhaust duct to route the spent air to the exterior of the home. This should be the optimal set-up for your situation. You have no negative impacts on your interior conditioned space.

Hope this helps!


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