Boiler efficiency

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f0zzy

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Probably a dumb question... but ...

We have quite a large open plan area in our house which at times can be slow to heat up. Our builder advised us that most efficient way to handle this was to turn boiler (Oil) thermostat to max, and then use room thermostat (wall mounted) for this area to control the temp within this area. AFAIK, this room thermostat controls pump which supplies radiators in this area.

Can anyone comment on this ? Does this make sense. My concern is that with boiler thermostat at max, we may be burning too much oil.

Thanks for all advice/feedback/comments/info ...
 
Our plumber recently told me the thremostat on our (gas) boiler only controls the temp the water is heated to but maybe thats rubbish or not the case with your situation. Someone else will know more I'm sure.
 
Our gas combi boiler is used in the way that your builder describes.

The coldest space in our house is the hall, so the thermostat is placed there, the boiler is turned to max and is on whenever heat/hot water is required. All upstairs rooms have thermostatically controlled radiators; all downstairs rooms have skirting radiators without thermo valves (old original system).

Since replacing all single-glazed windows with double glazed we have found that with the hall thermostat set to 16C every room in the house is comfortable.

Whether this would follow for your oilfired system I don't know, bit I would have thought that results would be similar.
 
Never Never turn your boiler thermostat up to max to compensate for having inadequte heat emmiters in any particular area.

If other rooms are comfortable then you can only increase rad output in the colder area or install fan convertor heater to quickly bring up room temp

Ask a competent plumber to look at it
 
If you feel it is taking too long to heat your rads may be undersized.

There are various back of the fag box methods for calculating rad size and of course there are proper calculations that should be made regarding exterior walls, insulation, windows, doors, interiror walls etc.

You have to laugh at this guide from SEI www.sei.ie/uploadedfiles/InfoCentre/RadiatorsSizePosition.pdf Firstly they state poor installers oversize then they give back of the fag box calculations. It's worth a read. The important line is "This calculation produces a heat loss figure
in watts, of how much heat you need to warm that room up to the design temperature from -3 deg C in one hour" So in theory you should be able to walk into that room when the temp outside is -3 deg C and within one hour the room will read the desired temp at the thermostat. I think they assume your boiler temp is set high but not max. Most cals would be looking for 70 deg water temp.
 
davidoco said:
If you feel it is taking too long to heat your rads may be undersized.

There are various back of the fag box methods for calculating rad size and of course there are proper calculations that should be made regarding exterior walls, insulation, windows, doors, interiror walls etc.

You have to laugh at this guide from SEI www.sei.ie/uploadedfiles/InfoCentre/RadiatorsSizePosition.pdf Firstly they state poor installers oversize then they give back of the fag box calculations. It's worth a read. The important line is "This calculation produces a heat loss figure
in watts, of how much heat you need to warm that room up to the design temperature from -3 deg C in one hour" So in theory you should be able to walk into that room when the temp outside is -3 deg C and within one hour the room will read the desired temp at the thermostat. I think they assume your boiler temp is set high but not max. Most cals would be looking for 70 deg water temp.
Click to expand...

I checked our Rad temps with a thermo gun and we're getting ~70 degrees in each of the two HUGE rads in this area. however typically during a coldish day in winter it heats room temp by only 1-2 degree's an hour. On a cold day heating needs to be on for a long time (3-4 hours) to get it to a comfortable 18-19 degrees. There is a lot of glass (good for summer) in this area and we suspect some heat loss is part of the problem. We compensate for the rads by using a gas fire to get room up to reasonable level but rads on their own really struggle. Rest of house is fine though. Its a "modern" house with double glazing etc through out.
 
f0zzy said:
There is a lot of glass ....rest of house is fine though. Its a "modern" house with double glazing etc through out.
Click to expand...

Remember that the best glass you can get lets out about about 5 times more heat than your average wall. The average double glazing lets out about 9 times more heat than your average wall.
 
Yeah - sounds like the extensive use of glass and maybe other issues with general insulation could be a key issue here. Certainly one to check out. Could you monitor things for a few evenings with heavy curtains pulled across such glass areas for example?
 
ClubMan said:
Yeah - sounds like the extensive use of glass and maybe other issues with general insulation could be a key issue here. Certainly one to check out. Could you monitor things for a few evenings with heavy curtains pulled across such glass areas for example?
Click to expand...

We tried that for a while. It helped a little but not a lot. We ended up replacing these with thermal insulated backed blinds.

Sounds like we might need an engineer and/or plumber ... ouch !!

The flip side on this, is we need very little if any heating apr-october in
this area due to solar gain on the glass.

Much appreciate all the replies & info.
 
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