We've got an insulated house, heat it properly, ventilate it, but still see humidity levels of 70%+ in bed rooms. How to fix that?
We've got an insulated house, heat it properly, ventilate it, but still see humidity levels of 70%+ in bed rooms. How to fix that?
We built a house 7 years ago and it's insulated and has double glazing. I've installed Home Assistant with temp sensors in the bed rooms and seeing 70%+ humidity levels. Temperature is always above 16c
We ventilate it, but still it's 70% in the bedrooms. WHO recommends 40-60%, so we're a bit worried.
Living room is around 55% during the day when we have the heat pump set at 21c.
As it's pretty humid outside I think it's almost impossible to get it lower, but are there any other tips? I don't want to run dehumidifiers. Would an HRV like system help?
So your house is insulated and warm, and presumably pretty sealed. I think you should be considering sources of water vapour.
Some common sources:
- Shower
- Drying clothes inside
- Cooking
If you have a separate shower (rather than shower over bath) you can get a shower dome which significantly reduces steam leaking outside the shower. I don't much like using a shower with one but they are effective. You can also get a more powerful extractor fan, though even the super powerful ones don't seem to be that powerful (I want one that sucks your clothes off).
If you dry clothes inside, try not to. If you have a dryer that isn't a condenser dryer, try to vent it outside or at least open the window. Probably try to use it less though using it less and not drying clothes inside don't make for many options in the winter.
For cooking, make sure you have a rangehood to catch the steam from any boiling pots. And make sure it's externally vented. I have lived in placed with rangehoods that just push the air back into the room (I'm not sure of the point...) but I'd think with a house that new it wouldn't be an issue.
You might have other ideas about sources of water. Gas heaters can be one but it sounds like you heat with a heat pump.
An HRV/DVS can help but I'm not sure it's as effective in a newer house.
You also mention the living room is 55% in the day when heated to 21c, what temperature are the bedrooms when they are 70%? Colder air can hold less water, and so the relative humidity is higher with the same amount of water in the air.
What do you mean exactly you ventilating. Mechanical ventilation?
Modern houses NEED mechanical ventilation. It's a travesty that new houses in NZ don't come with mechanical ventilation as standard, as is done in the rest of the developed world.
It's pretty obvious if you think about it. Seal the house well, well insulated, double glazed. How will the moisture leave without ventilation. This is why modern houses NEED mechanical ventilation. Older houses don't need mechanical ventilation because the house is already leaky.
And not the silly DVS thing. I don't want rat infested air from my attic thank you. I don't care how good the filters are. Ventilation from the outside please.
What this looks like is intake vents in the soffit, a duct, and fan that pumps fresh air in for positive ventilation. Our you can do negative pressure where it pumps out, or balanced where you have air coming both in and out. You can install a mechanical heat recovery system if the house gets cold.
Full HVAC includes ducted heating/cooling.
TLDR: your house is humid because it's well sealed and the builders couldn't be bothered putting in mechanical ventilation because we are 20 years behind the rest of the world.
If you already have mechanical ventilation then it is likely not installed properly. Just putting it in doesn't necessarily mean it's sized correctly for example.
Hvac is oversized and not running long enough. Super common issue especially when people tighten up their house