Heating issue

[maddog1996]

Can anyone give any advice please . I've got a 3 bed detached house and had a new boiler 2 years ago .
It's taking forever to get house upto temperature for eg. 12deg at 8 am heating put on at 20degrees and yet now at 1130 it's still only 14 degrees .
It seems like I'm using gas for hardly any heat . If this heating is on all day it never reaches full temp until 8/9pm at night .
Can anyone advise on cavity wall etc the outside walls always feel stone cold to the touch . New double glazing installed 5 years ago too with new front door last year also

Are the rads getting warm / hot?
If not check the TRV's, if someone has turned them down (to save money!) then the boiler will be working it's socks off but the rads emitting little / no heat.

Also check the thermostat on the boiler. The higher it is, the warmer the radiators will get and the quicker the house will warm up.

Rads getting hot and they have been bled . The temp on the boiler is nearly upto max for the heating

If the rads are getting hot then you can eliminate them and concentrate on the fabric of the building, draughts, insulating curtains etc.

Cheapest thing you can normally do with a house is loft insulation.

Check your loft and see how much is in there.

Also a bit more info about the house, what is the age ?

when was the boiler last serviced?

maybe you need to keep the heating on at night.
even if at 15 degrees it will take the boiler a lot less effort to go up to a more pleasant temperature.

reduce drafts, close airvents in windows for most of the day (it's more efficient to open windows a couple of times a day for s few minutes anyway)

House is around 30 years old

Serviced last June .. never have vents open

We had new loft insulation around 10 years ago . Not sure how long it's meant to last

Should last a long time, question is how deep it is. I think these days they recommend about 250-300 mm deep for newbuilds. 30 year old house may have a non insulated loft hatch as well.

Do you try to keep heat in the rooms ? For example I always close the doors in the living spaces and have draft excluders on the doors. I don't try to heat the hallways and obviously the rooms are much warmer.

I don't think that a 30 year old house should be that bad for heat leaks. Really you have to go around finding which bits are the coldest and finding ways of insulating them/stopping the heat leak. An IR laser spot thermometer can help with this. It does make quite a difference as you close off the individual gaps.

If the radiators are fully hot, all over (too hot to hold for long) top, bottom, sides and middle, what do they bring the room temperatures to?

Are the internal doors shut, or are you open plan?

The radiators might be undersized. Often they are calculated to provide an internal temp of 20C when it is zero C outside (an increase of 20 degrees). Recently it has been -6 at night so they would only provide enough heat to bring the rooms to 14C. Older houses were often intentionally colder.

Have a look at your gas meter. How much gas do you use per average 24 hour period? (Preferably check weekly while you are investigating)

As for CWI, when I had mine done, the heat demand for a 20C rise dropped from 16kW to 12kW.

Using a calculation tool, but I think pretty accurate.

Loft and CWI make the biggest difference, and apart from draughtproofing, have the fastest payback.

Unless you are in a wet or exposed area, a 30 year old house should have good walls without defects liable to cause damp.