Heating home in winter while vacant

I have had mixed reviews of VMCs - I wanted to install one but my sparkie advised against it. He suggested that they can make a house very cold in the winter as they normally draw the warmer higher air away from ceiling vents.

As it is warm here now I would be interested to know if a VMC could cool bedrooms as our first floor is so much hotter than the ground floor and outside.

Ventilation Mécanique ContrÎlée

VMC - I’ll be interested to learn too
 not something I have personal experience of
 :thinking:

Well when it is -20 outside we do like to have some heat! Jumpers are all well and good, but not quite enough. :slightly_smiling_face:

In the years before we moved permanently we left heating off most of the time we weren’t here as we had lovely neighbours who would put it on if the temperature dropped too far. We never had any issues with mould, but it’s a dry house. Now we have an air source heat pump we do have to leave it on all the time, which infuriates me.

I meant when people are away back in their centrally heated UK homes.
Why do you leave on the air source?

If there permanently then spending the extra on a heat recovery (double flux) version will retain 70-80% of the heat otherwise lost.
For a part time occupied property the low energy use of a std VMC around 35w would help but finding the issues like Stella found for the cellar damp, leaking rain water, roof windows should be prime objective

Because otherwise the pump freezes


I suppose that’s down to the machine manufacturer and the lower limits of their model but buy a trace heat tape, wrap insulation around it and that will solve the issue. Heat tape is low energy and self regulating. Plenty of farms use it for water supplies and combi boilers around condensate pipes ( if you have a decent plumber)

Yes if I don’t have to I wont The bills were higher than my house here in the US which is 3x the size! JUst afraid of damp / mould issues. Perhaps the solution is just frost gel for winter with dehumidifier and / or having my neighbors pop in and heat it when it drops at night (Mainly during H/C hours - that would be ideal!)

Or centrally heated US homes :wink:

I do have a newly installed VMC - that should help with mold issues, no?

Thanks!

Yes - high on my list of things I am trying to get done is add a proper door to the cellar. RIght now there is some sort of old door that is so heavy I cant lift it (Access to cellar is a square hole in the kitchen floor - is this normal?). Also prob not doing much to hold in the heat


I know loads of people here (23) who never leave any heating on over the winter, maybe the VMC if they have one, and don’t have any problems with mould. The problem with leaving heaters on is that warm air carries more moisture, which will then condense onto cold stone walls, allowing mould to grow. Better off leaving all forms of heating off IMO, save shit loads of money too.

Funnily enough (Or not) there were a uk couple who owned a holiday home locally, who thought they knew it all. When they burnt through €1500 of gas (in 2 months) on a frost setting - it was -20 , the pipes froze (They thought it was ok to leave the water on too), the boiler stopped, the pipes thawed and everything was flooded, along with a massive water bill.

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Yes it should, if you haven’t already bought some, get some hygrometers and watch the humidity, get it down around 50-50% and you should be good. Mould needs heat to grow and humidity above 60%

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Look for a sealed hatch/cover

Not at -20.

Someone’s in an argumentative mood, yes they can. I have heat tapes that can go to 125 C.

I’m not being argumentative, but I don’t see how putting a bit of tape round an air source heat pump that is 1.5m sq will make any difference when temperature falls to -20. It’s sitting in it’s own well insulated room after all. The only thing that stops it freezing is having some warm water circulating through it.

Jane, you did say air source, does it feed radiators or underfloor heating?

Underfloor mainly, those there is a radiator circuit that isn’t used much.

Ok the refrigerant side won’t freeze until around -50C so the only part that would require heating is the water filled components, I am assuming there is an indoor unit? If you say what heat pump you have we can look at the schematic.