A couple of weeks ago I’ve posted here regarding humidity in our house as I noticed it went up to ~75% indoors. I’ve bought a dehumidifier, but noticed that the humidity went up again after dehumidifying a room to eg 60%. Then, I installed a temp/humidity sensor outdoor and also calculated the absolute humidity to be able to compare easily. And… then I noticed when it’s moist, like now, the outdoor humidity would be close to 100%. Thus, it would almost be impossible to get it <60% indoors, unless you would heat it to 25c +
Right now, it’s 99% humidity @ 11c outside, which comes to 9.9g / m3 absolute humidity:
In the bedrooms it’s 16.4 @ 65% which is as expected. In the living room it’s 21c @ 55% which is almost the same absolute humidity as outside:
Still, it’s important to heat your rooms to ensure RH doesn’t reach 100% as that may cause dampness/mould. I’ve installed temp sensors & panel heaters in all rooms and set the min temp to 16c.
You probably know this?
Ensure you “flush” you house with cold fresh air once a day if possible. As this cold air is reheated it becomes much drier (relative humidity).
Living in the South of the South with a very soggy winter we are able to maintain around 50% RH with just a heat pump for heating and no dehumidifier.
Yes, I know, that’s why I’m comparing absolute humidity. It’s almost the same inside & outside.
I haven’t read your previous post - perhaps that’s the problem, but I’m a bit confused by this post.
You say:
But then say:
These two statements conflict?
Side Note: Less than 60%RH is the recommended acceptable indoor air quality.
If you flushed your house when the temperature outside was 11C outside @ 98.9%RH and then warmed that air up to 21C you should have a RH of around 54% as you have said you do. If you flush your house when it’s 9C outside @ 100%RH then warmed that air up to 21C you should have a RH of 48%. So a little temperature difference can make all the difference.
Sorry, I’ve probably missed something, and it sounds like you know all this. Just comparing our experience where we typically run the heat pump at 18-19C at night when we are awake and let it idle down to 15C when asleep. Typically, (but not always) flush the house during the day and maintain around 48%RH. Perhaps, overall, the air is a little “drier” down in the South?
Thanks for your reply! Yes, you’re right, my message conflicts. What I meant to say was that in bed rooms it can be 60+% and that’s fine. The recommended temp for bed rooms is 16c and if it’s 100%@11c outside it’s almost impossible to get it below 60% @ 16c.