Consumer Homes.

Question:

Are Air-to-Air exchangers connected to a house’s HVAC ducts or do they require a separate duct system?  Air-To-Air exchanger here means a heat recovery ventilator that can also transfer moisture from the incoming air flow to the outgoing air flow in the summer and moisture from the outgoing air flow to the incoming air flow in the winter.  I ask this question because I read a book this past weekend that showed a diagram titled "Balanced Ventilation System with Heat Recovery via an Air-To-Air Heat Exchanger". The diagram showed the Air-To-Air Exchanger had a separate duct system.  Under the title it also said "The ventilation system has a separate duct system and is not intergated with the heating and A/C systyem".   I interpret this diagram to mean Air-To-Air Exchangers require a separate duct system.  Or can an Air-To-Air Exchangers be integrated with the heating and A/C system?  If it can where in a house’s HVAC system are the connections to the Air-To-Air Exchanger made?

Response:

Thanks Bill, I was hoping you would respond.  You seemed to have had a lot experience with many of the newer products that aren’t standard in newer houses and I am grateful I can learn from your experience. – Hide quoted text — Show quoted text ->X-no-archive: yes > Are Air-to-Air exchangers connected to a house’s HVAC ducts or do they require > a separate duct system? >Both, usually.  They have their own "return" ductwork that draws air >from various spots in the house which is passed through a heat exchanger >and then vented outside.  They draw fresh air from outside which is >passed through the other "side" of the heat exchanger and then is dumped >into the air return on the furnace/AC. >– >Bill Seurer           Compiler Development             IBM Rochester, MN >seurer AT us.ibm.com                                  Bill AT seurer.net

Response:

Air-to-airs (HRVs) can be hooked up 3 different ways:     1. Stale air drawn from furnace ducts and Fresh air to furnace ducts     2. Stale air drawn from separate ducts and Fresh air to furnace ducts     3. Stale air drawn from seperate ducts and Fresh air to seperate ducts All three work, #3 would be best but most costly.  I had one installed in my house, using method #2, it works great and I love it … save energy, healthier home, less moisture problems.  It’s got to be installed correctly … not the best project for a do-it-yourselfer. R. Fromm, Customer Service Efficiency Connection / EnergyMatch "Energy Saving Ideas, Contractors who can help" www.energymatch.com    1-888-603-5519 – Hide quoted text — Show quoted text – > Are Air-to-Air exchangers connected to a house’s HVAC ducts or do they require > a separate duct system?  Air-To-Air exchanger here means a heat recovery > ventilator that can also transfer moisture from the incoming air flow to the > outgoing air flow in the summer and moisture from the outgoing air flow to the > incoming air flow in the winter.  I ask this question because I read a book > this past weekend that showed a diagram titled "Balanced Ventilation System > with Heat Recovery via an Air-To-Air Heat Exchanger". The diagram showed the > Air-To-Air Exchanger had a separate duct system.  Under the title it also said > "The ventilation system has a separate duct system and is not intergated with > the heating and A/C systyem". > I interpret this diagram to mean Air-To-Air Exchangers require a separate duct > system.  Or can an Air-To-Air Exchangers be integrated with the heating and A/C > system?  If it can where in a house’s HVAC system are the connections to the > Air-To-Air Exchanger made?

Response:

Thanks for the response.  You confirmed my suspicion.  The fan in the furnace, air handler, has to run continuously to exchange all of the air in a house.   Other wise there could be dead spots in a house where the stale air doesn’t ger replaced.  I agree with you method two appears to be the most cost effective method.  I have a lot of doubts about method one.  The first thing I thought of was pulling stale air from a HVAC return duct and pumping fresh air into a supply duct.  But then I realized the fan in the air handler could easily  over power the fan in the air exchanger and negate all benefits of an air exchanger.  Hopefully manufacturers have better methods of implementing method one than my first thought.   says… – Hide quoted text — Show quoted text ->Air-to-airs (HRVs) can be hooked up 3 different ways: >    1. Stale air drawn from furnace ducts and Fresh air to furnace ducts >    2. Stale air drawn from separate ducts and Fresh air to furnace ducts >    3. Stale air drawn from seperate ducts and Fresh air to seperate ducts >All three work, #3 would be best but most costly.  I had one installed in my house, >using method #2, it works great and I love it … save energy, healthier home, less >moisture problems.  It’s got to be installed correctly … not the best project for >a do-it-yourselfer. >R. Fromm, Customer Service >Efficiency Connection / EnergyMatch >"Energy Saving Ideas, Contractors who can help" >www.energymatch.com    1-888-603-5519 > Are Air-to-Air exchangers connected to a house’s HVAC ducts or do they require > a separate duct system?  Air-To-Air exchanger here means a heat recovery > ventilator that can also transfer moisture from the incoming air flow to the > outgoing air flow in the summer and moisture from the outgoing air flow to the > incoming air flow in the winter.  I ask this question because I read a book > this past weekend that showed a diagram titled "Balanced Ventilation System > with Heat Recovery via an Air-To-Air Heat Exchanger". The diagram showed the > Air-To-Air Exchanger had a separate duct system.  Under the title it also said > "The ventilation system has a separate duct system and is not intergated with > the heating and A/C systyem". > I interpret this diagram to mean Air-To-Air Exchangers require a separate duct > system.  Or can an Air-To-Air Exchangers be integrated with the heating and A/C > system?  If it can where in a house’s HVAC system are the connections to the > Air-To-Air Exchanger made?

Response: