air makeup for radiant heat

Tim_5

Does anyone have any comments or leads on units to keep fresh air make up on a home with radiant heat and tightly insulated.



Tim

BillW

Ventilation for radiant heated, superinsulated home

Hi, Tim.  There are several brands of enrgy recovery/heat recovery ventilators on the market.  All require at least some ductwork, and an intake and exhaust outside that must be above the snow line and away from any other vents for dryers, kitchen fans, pet areas or combustion appliance and automobile exhaust.  Which type you choose depends on where you live, based on the humidity.  Typically, an ER/HR ventilator is about 80% efficient.  HR units tend to dry out a space, ER units tend to balance humidity.  If the ventilator is ducted into your AC system, it will deliver fresh air thru all your ducts, and it is vital that your ductwork be properly indulated to avoid condensing water problems.  Also, these units are about 80% efficient, so the incoming air may feel cold on extremely cold days in the winter. A small hydronic reheat will cure this problem,by tempering the air as needed.  These units typically run 24/7 on low speed, with the high speed option controlled by a timer, manual switch, or from certain better quality thermostats.

Depending on the size of your home, you may need more than one ER/HR ventilator. Most units deliver about 200 cfm on low speed, and don't require any help from your system fan. How many people are involved?  Another important point is that you do not put the house under either a positive or negative pressure, so air balancing is required.  There are units that contain advanced filters and ultra violet lights to kill bioaerosols.  These require proper maintenance to function properly, and UV lights lose effictiveness over time, and while they may still light, they aren't producing the correct UV wavelength to kill bioaerosols.  I hope this was helpful.

Rhomar Mike

Low Tech

fellas, other than using a HRV can you recommend a low -tech method to accomplish the same thing?  Would a small wall vent with a damper work? Or some other "off  the grid " idea ?



Thanks, Mike 

Larry Weingarten

low tech

Hello:  One low tech approach is to have a tall house and openable windows high and low.  I do this and it works fine but possibly for the three cats. I've one friend who senses "something" in the air here.  Otherwise the air is dry and only the gas stove uses indoor air for combustion.



If radon is a concern, subslab exhaust could be used to slowly move old air from a house; giving a two-for-one.



Linda Wigington at Affordable Comfort is working on "The Thousand Home Challenge" which aims to greatly reduce home energy use, but of course, indoor air must meet some acceptable minimums.  There do not seem to be such guidelines for all types of potential pollutants.



Yours,  Larry

Coany

EZ air?

not sure if they're still in business.



 they used to make nice small, top of a closet, sized model.



 the same air to air heat exchanger others have mentioned here but in a more compact unit.