Energy Costs and Humidity for Fresh Air Intakes

[rrz]

Ok, now I'm totally confused. Again, I live near Chicago, so we have really cold winters and very humid summers.

My HVAC professional suggested two options, a fresh air intake that simply has a counter weight which effectively opens wider when air needs to be drawn into the house (i.e., when the heater or clothes dryer is pushing hot exhaust out). The second option would be a fresh air intake with an electronic humidity control (the damper stays closed if humidity outside is too high).

I'm concerned about operating costs that might increase by adding either intake and increased humidity by adding the basic air intake. Historically, I have not had problems with the relative humidity in my house.

A post below indicated that adding an ERV (versus no fresh air intake) would increase energy costs about $100 a year for a house near Chicago (I have no idea what size house).

http://www.toolbase.org/ToolbaseReso...tDetailID=3022

My HVAC professional stated that he believed an ERV would be overkill. When I contacted one of the manufacturers of intakes/ERVs that was recommended below, their tech support told me that I should definitely not get a regular fresh air intake if I live near Chicago...that I would experience significant increases in energy costs and potentially in controlling humidity and instead, I should consider an ERV which would pay for itself over 2 years (marketing hype??).

That would suggest adding a regular fresh air intake would cost in excess of $500 a year!!

What kind of energy cost increases could I expect by adding a fresh air intake that is not an ERV? Would an ERV really pay for itself...What about maintenance/repair costs as well that makes this a waste of $1,000+? I think all of us prefer KISS (keep it simple stupid)

What do you recommend...fresh air intake($300), one with humidity control ($500) or ERV($1,000+)?

At this point I'm considering forgetting about the entire fresh air concept and saving my money. Help please!!

[rrz]

Oh yeah, one more thing...I've been looking into the minimum recommended distance between a dryer exhaust vent and a fresh air intake and see most references to be 8 feet. Any thoughts?

[rrz]

I'd appreciate any advice based on your experiences in installing fresh air intakes and ERVs.

[d_griff]

what do you mean by erv???
i think if you could get a enthalpy control with mixed air sensor in your duct that controls some sort of modulating motor damper for outside air you would be ahead of the game,definitly do not go with the counterweight. if it is 90 degrees out with 90% humidity you would suck that into your house when you are trying to cool it..and the same in extreme cold,you need something that modulates and does so with sensing capabilities so it does not overheat or overcool your house with outside air

[paul42]

When your dryer, bathroom exhaust, or range hood exhaust is running, outside air will come in somewhere to replace what is exhausted. With a fresh air intake, you have some control over where it comes in.

An HRV might pay for itself in Chicago over a period of several years, but I don't think an ERV ever would.

[big johnson]

What are trying to accomplish? It's not clear to me in your thread. Do you want to control humidity, indoor air quality, energy usage or all of the above? Are you uncomfortable with the way your system operatees in extreme weather?

[rrz]

I'm trying to increase indoor air quality by allowing more fresh air to enter my HVAC system. I'm not uncomfortable with the current heating or cooling (from a temperature or humidity perspective).

I'm afraid that if I add a fresh air intake, I'll not only screw up my humidity, I'll also significantly increase my energy costs.

[airon]

HRV (heat recovery ventilator) is commonly used in the midwest and is desirable in colder climates when #1 home is of newer construction #2 a lot of humidity generated in a home.
Some parts of the country have made them mandatory in building codes. At the same time some have removed them from the code.
All homes have a certain amount of air infiltration around windows, doors, etc.. An energy study can be done to determine infiltation rates which in turn will determine fresh air requirements. Generally speaking in my opinion, the "average" home has enough air intake through leakage to meet most fresh air requirements. If you have an older gas furnace and water heater you allready should have a fresh air intake as well for combustion air. A newer 90+% furnace will draw its own air from outside.

I question the requirements of these units where they are often used as a source of make up air rather than an air exchanger.As they exhaust equal to what they put in.

So the question becomes comfort. If you like fresh crisp air then they (HRV) are possibly the best home option available for comfort with minimal energy loss in the heating season. a properly sized unit will replace the air in your home completely every couple hours or less of run time on an as needed basis. A motorized damper shuts off outside air when not in use.

Maintenance is minimal with an annual filter change or cleaning. Can be set up to run stand alone, with the furnace A/C or on a humidistat or timed operation inside the house.

We sell a bunch of these every year but base it strictly on an energy study or as a comfort option. Commercially a % of fresh air is a requirement and in many locations we strongly reccomend HRVs.