Any HVAC Pros on here?

[Atrus]

I have a new construction home (moved in Jan 2019) that gets very dry in the winter. We've had the heat on for a couple of weeks now, and the house has already dropped ~10% (currently at 30% RH).

The house is running geothermal HVAC. My understanding is some believe traditional humidifiers do not work well, and a steam unit is required due to the geothermal having lower temps than a propane/NG forced air unit.

Any recommendations as to what I should look at installing? It's a Bosch 6-ton geo unit, and we're running a Sensi smart thermostat, if that helps.

 

[Beigg]

I don't have much knowledge as to a perm solution, but ya could put the family on a soup based diet by making soups from scratch throughout the week. Also, boiling noodles for the mac-N-cheese dishes.

 

[Atrus]

Haha, not gonna lie, it's crossed my mind. We usually do make large pots of soup periodically and freeze it for future meals.

I brew beer too, so maybe I need to up my game there..."Honey, I really need to drink up this last batch so I can make more. It's for the air quality in the house!!"

 

[avbcon12]

Having built Geo unit homes, one cause I've seen for dehumidification can be longer fan run times. Make sure the blower motor/fan isnt set to run any longer than the compressor is on. Between this and possibly slowing down the fan you could see about a 10% increase in RH.

One client of mine had set their blower to On in the winter, not Auto thinking the more air circulating led to more consistent temps throughout the home. It didnt, all it did was cause more air to travel past the coils constantly which continued condensing the air (pulling out moisture). We set the fan to auto and the RH rose by 10%

 

[soap]

This is really odd. Normally geothermal houses keep pretty good humidity levels in the late fall and winter since the heat unit does not dry out the air. I have geo and our humidity is normally in the 40% range in the dead of the winter. We have a traditional pass through humidifier.

What type of insulation do you have? We did closed cell spray foam (which also helps with humidity).

--Joe

 

[avbcon12]

That brings up a good point. Depending on how tight your house is, do you have an air to air exchanger? If you do, during the winter months you may want to turn that flow rate/run time down.

 

[Atrus]

Having built Geo unit homes, one cause I've seen for dehumidification can be longer fan run times. Make sure the blower motor/fan isnt set to run any longer than the compressor is on. Between this and possibly slowing down the fan you could see about a 10% increase in RH.

One client of mine had set their blower to On in the winter, not Auto thinking the more air circulating led to more consistent temps throughout the home. It didnt, all it did was cause more air to travel past the coils constantly which continued condensing the air (pulling out moisture). We set the fan to auto and the RH rose by 10%

Interesting, I never would have thought that'd be an issue with heat - I could see it with A/C potentially. I do have it set only to run when the heater is in (meaning, it's set to "auto")

This is really odd. Normally geothermal houses keep pretty good humidity levels in the late fall and winter since the heat unit does not dry out the air. I have geo and our humidity is normally in the 40% range in the dead of the winter. We have a traditional pass through humidifier.

What type of insulation do you have? We did closed cell spray foam (which also helps with humidity).

--Joe

Good to know a traditional pass-thru seems to be working well for you. I may go that route and see how it performs. We have closed cell foam in the walls, blown-in-cellulose in the ceiling. Exterior is also sheathed with 1" rigid foam. Honestly, the house should be pretty air-tight. We do have 2 natural fireplaces, so that hurts it. Drove our builder nuts that we wanted those.

That brings up a good point. Depending on how tight your house is, do you have an air to air exchanger? If you do, during the winter months you may want to turn that flow rate/run time down.

We do not have an air to air exchanger