Isolating the source of a cold house

ChewyLuey

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.

Idbatterim

is the boiler oil or gas? The boiler sounds archaic either way! take a look at heatandplumb.com They seem to have fantastic prices on boilers, I think they ship to Ireland. Replacing the windows is an expensive messy job, if doing this and money is an issue Id do it maybe in 2 stages, i.e important rooms to keep warm first probably bedroom's & living room (the rooms you will likely spend the majority of time).

Plombier

A single glazed window will have a U value of anything up to 6, so if you have 10 Msq of windows at design conditions over a one hour period the heatloss for the windows is 1.5 Kwh, with new windows with a low U value of 1.5 the heatloss will be 0.375Kwh a saving of 1.125 Kwh per hr this is just one element of the building if you add all your improvements together it amounts to quite a bit.

ChewyLuey

Thanks for the replies.
Its a gas boiler and a plumber who looked at it said it certainly is a dinosaur and a not overly well known model either. I suppose it would be a good starting point to change this.

sky6

I would start by power cleansing the Rad system. Then increase the Boiler size to an 80 or 90 th btu Condensing Boiler. I suspect what you have is only a 50 th BTU Boiler.
When you get to changing the Windows I would suggest you get Argon filled K Glass units. The cost is not that much more than regular glass but the benefits are noticeable.