Stove VS Half job of New Windows for keeping warm

Poor heat retention on older houses is usually always related to drafts.

cormie wrote: »

I would have thought new windows wouldn't have any drafts without needing airtightness tape

It's not the windows themselves that are being taped, it's the junctions between the walls and the window frames. So yes, they do.

Installing a new boiler if your house is a sieve is throwing good money after bad. You'll heat the garden more than you are today and it will cost you more.

You can make the house air tight without compromising ventilation. The ventilation will be needed outside of the air tight envelope to prevent the timbers from rotting.

You will of course need some ventilation within the envelope also to prevent damp. That's where trickle vents etc come in but they won't do anything for your joists.

cormie wrote: »

Greebo, thanks, you've lost me a little with the ventilation vs airtight and trickle as a solution to ventilation but not helping with keeping joists dry... what would you suggest here?

/edit
Might be a good idea to have a cup of tea on standby!


So assuming you had a perfectly sealed living area within the external envelope of your house you have two distinct areas. The warm area where you live and the cold area thats outside the living space but within the house structure.

The warm area is actually wet and warm as cooking, cleaning, breathing, etc all produce water vapour. If you dont replace this or vent it you will get mould issues in the house. Nowadays (typically in new builds) people use MHRV (Mechanical Heat Recovery Ventilation) to swap warm wet air for warm dry air. Other than this the options are to allow warm air to be replaced be cooler dry air from outside.

The other area is the cold area within the house, in your case this would be the attic and under your suspended floors. These areas need ventilation for similar reasons, there is water vapour or in some cases water that needs to dry. Thats why your attic is vented to the outside and is (should be!) significantly colder than the rest of your house at the moment. There is literally wind blowing in under the fascia/soffit and exiting via roof vents. This is keeping all the timber within the attic nice and dry and you dont care that its cold because all the insulation and the airtight membrane are keeping that separate from your living space. This is why you need to be very careful with spotlights upstairs, if they are not fitted properly they are acting like little chimneys and pulling all the warm air from upstairs into your attic and also allowing the cold air into the rooms.

Its similar under the suspended floor. If you take up your floor boards you probably have plain old dirt down there, anywhere from a couple of inches to a couple of feet below the boards. This ground will be damp unless its ventilated as the ground, especially in Ireland is naturally damp. If you look around the outside of your house you will see numerous vents just about the ground, these are to ventilate this space and prevent the joists and flooring from rotting. Problem is that, like your attic, you have an airtight barrier and then insulation, this ventilation is also ventilating the warm space within the house.


Regarding your window/door install. Its massively depends on who is doing it. Joes Window Co wont even be aware of thermal bridging and taping of seams and even if you ask them they wont have a clue and wont do it.
Even going with one of the more reputable companies might not make any difference, your house might not even have a vapour barrier in situ for them to tape to!

This is why I think you are better off spending money on a survey (a good survey). Sure it will cost you, but you will have the results of this survey for the lifetime of the house and can make knowledge led improvements to your house as and when you can afford them. Think of it as an investment.

Think how you will feel if you from 5K on new windows and the house is no warmer? What then, do the rest of the windows and doors, will that make any difference? It wont if they were never the biggest culprit to begin with!

cormie wrote: »

Thanks a lot for such a detailed explanation!!

So the roof is vented to allow air under the fascia/soffit, but you're saying this would usually pass through above the insulation on the roof, just to keep the wood in the roof itself dry, then it passes out through vents on top of the roof itself under the tiles say?

The attic is certainly colder than the rest of the house and there's no spotlights fitted, just one regular light in each room.

I've noticed in other new builds I've been in, that the temp in the attic is not a lot different to the rest of the house, whereas the drop in the house I'm referring to above, is definitely noticeable. But you're saying even a well insulated attic, it would be normal for a noticeable drop and this doesn't necessarily mean there's bad insulation and heat retention in the house?

With regards the suspended floors, I thought the initial mention of suspended floors above, was referring to the floor between ground floor and 1st floor, but now I'm thinking you mean the floor of the actual ground floor? I think I've seen what you're talking about in some houses, where under the floor boards there's a big empty space, however this house, once you take up the flooring downstairs (have seen both kitchen and sitting room wood floor removed) it's just concrete, so the flooring isn't being suspended from what I know? I've actually attached some photos of flooring in the kitchen taken up, as well as the outside of the house. I can't see any vents going under the floor, but maybe there are in other spots?

Definitely makes sense to get a survey done alright, but the homeowner is limited with a tight budget (hence only being able to afford 30% of the windows required), so if a proper survey could be done for €500, yeah I reckon that might be a wise option, but if it's going to cost much more, then they aren't going to have money to make any improvements and all they'll be left with for the foreseeable future is knowledge of what needs improvement :P

They did get some work done through the warmer home scheme, but this doesn't cover windows anymore as people were apparently going way over budget.

Ah, well it depends on if you have a warm or cold attic.
Older houses, unless they have had a retro, have a cold attic space.
This means the insulation is on the attic floor so its keeping the heat in the rooms below and not letting the heat into the attic. (Hence the water tank and pipes have their own insulation, to stop them freezing)
Some newer houses have warm attic spaces, where the insulation is between the rafters (in the ceiling) rather than the joists (in the floor). There is still ventilation above this insulation and below the exterior of the roof for the same ventilation reasons. So yes, assuming your attic is designed to be a cold space (insulation on the floor) you want the attic to be cold, almost the same temp as outside, otherwise you are losing heat into the attic. In winter you want your outside roof tiles to hold the frost/snow as long as possible as this means you are not melting it with your heating bills!

From the looks of your photos you dont have a suspended floor, you have a concrete plinth. This is good from a draft point of view as concrete floors wont be ventilated (and your pics indeed dont show any vents), but the question is now, is there insulation under this concrete! If there isnt then this will be a massive cold bridge into your home. (The laws of physics mean that heat will always transfer to colder places to reach equilibrium. This is why A/C is so expensive, you spend lots of money cooling the room down but physics keeps trying to warm it up again.)

An uninsulated concrete base means your heating is constantly trying to heat up the concrete which in turn is trying to heat up the ground. Heating an insulated concrete base is great as it will retain the heat for a long time and slowly release it back into the house as needed (a heat sink).

My point on the survey being an investment is, assuming the home is owned by the occupier, once you have the results of the survey you have them forever. Even if it means that you get the survey this year and cant afford to start works until next year, you know the works are the correct thing to spend money on.

What work did they get done do you know? Is it just the attic and wall insulation? Attic will have deffo helped. If it was me and money was super tight, I would tackle the open fire first. That is worse than having an open window in your house as a chimney is *designed* to suck hot air out of the room. You can get inflatable baffles etc that are DIY install if you dont want to just brick the whole thing up.

BTW, Don't get me wrong, new windows and doors will be lovely, it just might not make the house any warmer.

(Obviously if the windows and doors are poorly fitted at the moment and drafty it makes sense to do some remedial work, but this could be as simple as installing some foam strips for €5)