Hi
After really bad condensation problem in my house (I posted about a while ago)...we had cavity wall insulation but the condensation on windows etc was still bad so decided to go for it and had heat recovery ventilation fitted on Saturday.
So far so good, no condensation, but obviously only been two days yet!!
My question is, one of the things recomended when you have a condensation problem is to keep the heating on in all rooms for longer on a low setting. I have noticed it is much cooler in the bedrooms now (I like the bedroom to be cool so this is fine) but is it still necessary to have the heating on for longer with HRV? It just seems such a waste as one bedroom is only used occasionally and the other just as a dressing room at the moment.
Thanks for any advice
john11668
posted on 04-12-06
The moisture content in the air should reduce generally particularly with direct extract from bathrooms, kitchen and utility rooms. So condensation should reduce anyway without heat input.
A steady low level of heat would improve the bedroom situation but periodic ( twice daily)rather than constant should be fine and a TRV set to 1.5 should suffice. If you have a problem room then a small extract duct from that will help too as warm air from the heated areas will be drawn in to replace the extracted damp air.
Paul Teather
posted on 05-12-06
Primarni,
Something sounds very wrong!
There should be greatly reduced condensation and the bedrooms should 'feel' warmer than before (the reason being that the hrv should be supplying pre-warmed and relatively dry air to the bedrooms).
It might be interesting to do some monitoring (air temperature, humidity and surface temperatures) to find out what is realy going on before you spend any more money chasing the problem
As this is another companies HRV I will not comment on line; would you prefer to discuss it off-line? (0560 132 0859).
Primarni
posted on 05-12-06
Thanks for the replies - sorry, I obviously haven't been clear, we did have bad condensation before, but since having HRV fitted we have had NO condensation (so far since last Saturday!).
We have noticed it is a bit cooler in the bedrooms, but the system we have is only 70% heat transfer so I suppose this is to be expected, it's not that cold, just cooler than before but nice and fresh too.
I meant should we have the heating on to try and stop the condensation coming back, or is this not necessary now we have the HRV fitted. I suppose the answer is, as you said Paul, that the condensation shouldn't come back whatever the heating situation if we have HRV and it is working properly. I need a really cold day now to check that there is still no condensation!
Paul Teather
posted on 05-12-06
Sorry mis-read; but good news!
Please let us know what happens as the weather changes (I am assuming we will get a winter this year).
Was the system designed and calculated to be balanced and give the correct air flow into each room (or even measured?)- if not the lower temperatures could be due to an in-balance of air speeds across the heat exchanger (75% minimum is OK,others quote 'up to 90%', so little extra benefit)
OR
The simple fact that you are ventilating rather than storing up warm stale air could be the reason why it feels cooler - simply a price to be paid for ventilation. At least you will have less worries about air quality.
Primarni
posted on 05-12-06
Hi, yes good news hopefully!
The air flow was measured and calculated and we had it fitted professionally in the end to be sure it had been done properly. I think as you said it is just because the air is now fresh instead of stale warm air! We were sleeping with the window open before having this fitted, but as we have a black out blind the air wasn't circulating round the whole room like it is now.
At the moment, after a year of damp and mould, I hardly dare to let myself believe it is working - I will let you know when the cold weather comes - if the condensation stays away I will be the biggest advocate of HRV ever!!
