Exhaust only ventilation OK in 15.7 ACH50 home in Zone 5a CT?
jenniferz5
| Posted in General Questions on
My oil furnace finally gave up the ghost. I am replacing it with a Mitsubishi ducted P-series hyper heat pump with an Aprilaire Merv 13 filter on the return and (eventually) an AtmosAir Bi Polar Ionization system. I have a 24″ electric range with a 30″ ducted range hood (and the kitchen is closed off from the rest of the house), plus a Panasonic WhisperGreen bath fan in the sole bath. The house is a 1950’s ranch, 1400 sq ft. Is this enough ventilation?
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Replies
If your house really is 15 (almost 16) ACH50 then you undoubtedly have a bunch of low hanging fruit as far as air sealing goes. IMHO, balanced ventilation won't yield any perceivable benefits until you get that leakage rate under control.
Didn’t you already ask this question?
https://www.greenbuildingadvisor.com/question/negative-pressure-in-15-7-ach-50-home-does-it-matter-zone-5a-ct
You probably doesn’t need any active ventilation most of the year in your home. Certainly in winter, stack effect alone is going to be exchanging more air than a bath fan.
What are your plans for sealing the house up?
What was the heat load calculation and what equipment was specified.
The equipment I will be using is in the question above. I plan to add Rockwool to R49+ in the attic, along with Smart Baffles; Rockwool in the rim joists to code; eventually, Rockwool or cellulose blown in to the exterior wall cavities through the brand new siding.
I did ask the previous question and should have asked this question there! Too many things going on in my head right now.
You need an air sealing plan before adding any insulation.
The size of the equipment is what is important compared to the load.
In my own house in MSP I have an interior volume of 28,220 cubic feet. The ACH50 is 3.14 and I use no mechanical ventilation. There are 2 occupants in this house so ventilation requirements are lower than typical households. I agree with the other posters, get your air sealing plan in place. Make all of your envelope improvements and then size your new HVAC equipment. If you get the house down to 5 ACH50 you can then consider mechanical ventilation.