Dehumidifier necessary in new house?

Hey everyone,

So just recently I purchased a brand new house. The house has an HRV installed and a humedistat in the main living space. It's set to 40% humidity and it comes on for 20 minutes an hour. The home builder also bought us a dehumidifier for the basement and had it running. I put a power meter on ti and we're going to use around 300KWH from the dehumidifier alone. Its set to get it down to 40 but it pretty much runs nonstop and is at 48-50. My main concern is the electricity usage. Is running is a necessary evil? Id rather have a bit higher utility bill then have my hardwood floor shifting.

Thanks!

 

It seems strange that the builder bought a dehumidifier, for you. What does he know that you don't? Has he built any other homes in the neighborhood? You might want to knock on a couple of doors.

 

Builder was saying they provide them as they often had clients not controlling the humidity properly and they'd end up ruining the hardwood and such. Ontario has a pretty extensive new home warranty program so they seem to do whatever they can to avoid disputes.

 

40% is on the low end of the relative humidity range for human comfort. Generally a relative humidity (RH) of 40 to 60 percent is ideal for humans although anything over about 50% is conducive to growing mold. I would start by inching up the humidistat setting to 45% and not get too worried if you have to go a bit higher. Try for an RH of about 50% throughout the house. It is wild swings on the RH that causes problems with hardwood floors more than maintaining a set RH, even if it is a bit high.

 

don't run the hrv in the summer - it brings in moisture. the humidity control is for winter use - should cycle to keep moisture under control. in winter ventilation reduces humidity.

set the dehumidifier to 50 to 55%. Don't set below 50% - the capacity really drops as it gets less humid, so it runs longer and uses more kwh.

residential dehumidifiers aren't make to maintain low levels, the ratings are for 60% and 80f. At 50%, 70f the capacity is a lot less and below that even worse.

it's good to have to dry out the building materials. after a couple of years at most you shouldn't need it if you have a/c.

 

I agree with Furd that the 40% is on the low side favoring the builder, fewer problems with low humidity than moderate humidity.

Brand new homes will also be experiencing a drying time frame, if brand new, and summer air will be bringing in extra moisture.

Is your HRV on a timer that cycles its run time or runs 24/7? There should have been a determination as to how much fresh air is needed and even that number is not cast is stone as it assumes a certain number of residents and moisture related activities. If you have fewer people than bedrooms (I'd have to look up the other criteria) your fresh air needs might be better suited with less run time. And that could change comes winter. New homes are by design a bit more high tech. If outside air has high humidity that could be complicating the humidity issue. You could turn it off for a few days to see how that affects the dehumidifier.

Bud