Pinpointing why rooms are cold

Hi All

I bought a ~25 year old semi-detatched house in the summer. Some information about the house :

- Was rented for most of its lifespan from what I can tell with minimal improvements and cheapest way out taken for most aspects of it
- North/ South Facing. The kitchen and rear of the house is facing directly north
- Single glazed timber windows
- Very old "Warmflow" outside oil boiler. Possibly as old as the house itself.
- No heating controls, thermostat or TRVs on the (old) rads.
- During the winter the boiler has been set at the max (90 degrees)
- ~75 mm cavity with slab insulation on the inside of external walls (apparently popular construction in Cork at the time)
- I have already filled the cavity and insulated the attic with SEAI grant


The downstairs rear of the house never feels warm. Even with the heat going full blast. Obviously given the details above you might say that it is no wonder. There are any number of reasons why it wouldn't. However what worries me is I can't really pinpoint where the problem is. For example :

- Although the rads are old and I am aware newer ones convect off the hot air better, the rads are boiling hot to touch. Saying that you can stand a few feet away from them and not feel any warmth. Maybe they are undersized for the space.

- The single glazed windows do not appear to be massive source of heat loss (again this may not be tangible and maybe they are a huge factor but it doesn't exactly feel like there are huge tracts of warm air flowing through the windows or vice versa with cold air.


I suppose my concern is that when I spend a substantial amount of money on new windows, boiler and rads next year the house might still be cold. Are there companies who can do heat surveys at an affordable price to accurately pinpoint where heat is being lost/ why rooms are not warming up/ where to spend money first etc.
Also, is it possible that floor insulation or lack thereof could be a major problem here ?

Any feedback appreciated. thanks.

A thermal imaging assessment could tell you if there is a particular heat-loss problem areas. For example, if the insulation wasnt applied correctly and there is thermal bridging; if there are ventilative heat loss. Sounds like it might be money well spent but I dont know any reasonably priced ones.

In terms of heating/rads, if the house is cold then the problem is it is not retaining the heat. Try to solve the 'why is the heat you are creating leaving the house in the first place' question first.

The single glazed windows ARE a problem. I cant think of an instance where they wouldnt be. Think of it in terms of u-values (amount of heat loss through item). The U-value of a insulated wall is approximately 1 W/m2K while the U value of a single glazed window is in the order of 5W/m2K. That means the window looses 5 times as much as the same area of wall. [these wall values are rough, but you get the pint]. The thermal imaging camera again would show this.

The price of good double glazed windows are coming down. Shop around and haggle!

This should be simple enough to sort yourself.

Firstly the single glazing will be loosing a huge amount of heat. Get yourself a set of curtains with a heavy thermal lining, usually you buy the lining itself. Put them up and you should see a massive differance. Also put a sheet of paper in the window and close it, just about 10mm, if you can pull it out easily the window is also not sealing correctly and will all the time be allowing cold air to flow into the room. You will be able to reuse the curtains when you get your double glazing.

Nothing cools a room like cold draughts. Ensure there are no gaps between the frame and window. Reseal on the inside if required.

Radiators:

The system if 25 years old could have several issues.

Rads may be undersized, use a rad calulator to determine the required size in BTUs for you room and them compare to a a rad spec sheet such as can be found on quinn rads or biasi.ie.

If undersize you can only replace with a larger rad. Assuming your boiler is sized correctly for the house the only issue is that is will be of a lower efficiency and costing more to run.

The rads may be sludged up after 25 years, a powerflush of the system may do wonders, they may also need bleeding to release air in the rads, check for cold spots near the end of the rads (sludge) or the top (air).

If you have not, put 300mm of insulation in the attic asap. Hot air rises so if you stop it at attic level it will back up per say to the ground floor a lot quicker.

Finally draughts, these are your enemy. My technique was to light a roaring fire, cover the vent to force the air to be sucked from else where but remember about carbon monoxide so make sure you have a mox alarm and them go room to room with a gas fire lighter like you get from bic, I ran this around doors, skirting to determine where the draughts were comming from, in my case, it was under the skirting which I then sealed to the floor and from one room in particular which had a window with bad hinges, this part can be very time consuming but put in the time and you will reap the rewards quickly as even when unlit an open fireplace will always be drawing air in. But you need to cover the room vent to force it to draw from elsewhere.

Regards