Sat, 30 May 2026 23:16:57 +0100 https://www.greenbuildingforum.co.uk/newforum/ Lussumo Vanilla 1.0.3 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12461&Focus=207254#Comment_207254 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12461&Focus=207254#Comment_207254 Sun, 17 Aug 2014 17:09:12 +0100 Chunkylover
For heating we have been advised to install underfloor heating on all floors. With the current insulation regulations we're slightly worried of the possibility of damp issues should the property not have sufficient ventilation.

The question is should we be installing an MVHR system on top of the underfloor heating. ?? Or will trickle vents on the windows be enough to provide ventilation??

I feel if we have both installed one or the other may be seldom used.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12461&Focus=207258#Comment_207258 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12461&Focus=207258#Comment_207258 Sun, 17 Aug 2014 17:58:43 +0100 tony
I would want an airtight house and MVHR, if you have good U-values you wont need heating, possibly on the g/f only if bad U values.

Window vents are uncontrolled and virtually uncontrollable ventilation, too much when windy, none when it is calm.

You want MVHR]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12461&Focus=207262#Comment_207262 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12461&Focus=207262#Comment_207262 Sun, 17 Aug 2014 19:22:22 +0100 SteamyTea
Heat load is the sum of fabric losses and air losses
MVHR efficiency is is the integral of just air losses.

So it is possible to have a poorly insulated house but with good airtightness or a house this good insulation but poor airtightness. Or anywhere in between.

Get your detailed design sorted, work out the losses and then decide the best system to use. Hard work trying to decide the other way around.
Unless you want both, but as cheap as possible to run, then that will lead you to a very well insulated 'box' with very low ventilation losses.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12461&Focus=207271#Comment_207271 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12461&Focus=207271#Comment_207271 Sun, 17 Aug 2014 23:13:02 +0100 Chunkylover
Are you saying spend money on insulation and sealing the house properly and have MVHR system in place ?? With UFH installed on the ground floor only just in case ?]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12461&Focus=207273#Comment_207273 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12461&Focus=207273#Comment_207273 Sun, 17 Aug 2014 23:39:38 +0100 tony https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12461&Focus=207274#Comment_207274 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12461&Focus=207274#Comment_207274 Sun, 17 Aug 2014 23:49:34 +0100 Gotanewlife
Even with moderate air tightness (such as my retro fit scenario) MVHR is very valuable even if it doesn't necessarily have a payback (return on investment) in terms of saved heating energy paying for the capital outlay as would be the case in a really airtight house.

UFH is the best choice for heating if possible.

If you target minimum regulatory insulation values you're probably on the wrong Forum but that doesn't mean to say the high levels of insulation and build quality required for a zero heating house will be right for you either however with a 'self build' that should at least be your starting point.]]> https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12461&Focus=207276#Comment_207276 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12461&Focus=207276#Comment_207276 Mon, 18 Aug 2014 07:25:09 +0100 alec https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12461&Focus=207277#Comment_207277 https://www.greenbuildingforum.co.uk/newforum/comments.php?DiscussionID=12461&Focus=207277#Comment_207277 Mon, 18 Aug 2014 07:47:03 +0100 Nick Parsons
Lots of scope for really good results. Enjoy it!

Nick]]>