Insulating beyond the normal measures - what are the options?

ilikecookies

Looking for a bit of advice around insulating above and beyond the normal measures.

The context is as follows - we live in a 1950s 5-bed house, off-grid, in a fairly exposed location. Since moving here 3 years ago we've done the more obvious insulation measures: double-glazing, loft insulation and cavity wall. That said the house still feels cold and I think heat retention is poor.

As a result we burn through a lot of oil: 2500 litres/year which might not sound much for a 5-bed but that's generally only providing 5 hours of heating a day in the winter months at a setpoint of around 19.5 degrees (ie. not tropical by any means).

In the future we plan to carry out a fair bit of work on the property. I'm wondering what additional insulation measures we could look at. Cost will be an issue (isn't it always!) but at this point I'd like to get all the options on the table and go from there.

3 big measures I thought of were:

1) Insulating internally any external walls. For example using aerogel board and then decorating over that. I guess my only concern with this approach is ensuring there is adequate air flow/ventilation through the walls to prevent damp given that we already have cavity wall insulation.

2) In the loft we have the loft-floor (between the joists) insulated. Should we look at insulating up above (ie. between the rafters)? Again I wonder how to control the moisture.

3) Simply oversizing the heating system to a ridiculous degree! Sure the running costs will be high but these may be on a par with the cost of retrofitting additional insulation!

I imagine option 1 will be rather expensive and time-consuming but will have the biggest pay-off long-term.

But then again maybe I should start with one of these heat-loss surveys (using a sensing camera) as maybe the areas of biggest heat-loss are not where I think. For example, the problems might relate to a poorly insulated floor which will be pretty hard/expensive to retro-fix.

Any advice appreciated!

malc_b

The cheapest solution is to work out where the losses are using one the heat loss programs around, or pen paper if you wish. Programs are easier. Just measure rooms, windows, and choose what looks the right construction. That will tell you the heat loss at -1C. Then google degree days which is how you convert max heat loss into an average for the entire winter. If get a figure similar to what you use then ok, if not then you need to wonder why.

Once you have your house is heat loss program it also gives you a basis to look at improvements. You can say up the loft insulation and see the house loss before and after which gives you a percentage oil saving.

You mention controlling the moisture if you increase the loft insulation, the usual way to wedges to open the felting and allow more ventilation.

Also, you might want to try heating for longer. Houses lose heat until they reach outside temperature. So when you turn off the heat at night the house still loses heat (from the house fabric) and you go into heat debt. You have to make that up the next day. The difference between 24hr and 16/24 is 15-5%. The best insulated the house is 5%. Heating systems are usually designed for a -1C outside running 24hr, so if you are only running 5/24 the system has to work ~5 times harder. Even if the boiler is man enough I doubt your rads are 5 times bigger.

niftythrifty1

my tip for insulating a bathroom wall (where no cavity walls are)!

My house has no cavity wall insulation nor a cavity in the wall for that matter! its an 1956 built house good bricks but with having no cavity or insulation means it doesnt hold the heat like a modern house would and if thers one room in the house you like warmer than anywhere else its your bathroom especially as you spend time in there washing naked !

What ive decided to do is to put a 10mm insulation board onto my existing walls which are currently plastered. The boards have been fixed to the wall with a flexible powder wall adhesive and made sure ive covered the walls with a waterproof pva and water mix so the adhesive adheres to it well and using a 5mm notched trowel covered the walls with the adhesive then firmly pressed the boards to it. Once set the boards will then be ready to tile onto.
Ive only covered the walls that are an external wall.

Ihave only tiled one wall as yet as this is a feature wall and the pictures show my window wall which im currently working on.

I am a professional tiler and managed to get the boards at trade price which work out £8 per meter sq so not that expensive when you only have two walls like i do to insulate.

I realise insulating behind tiles can only take place if your changing your bathroom tiles, so to anyone having a new bathroom fitted this maybe a good choice for you.

You can either do the work yourself if your competent with a trowel and mixing adhesive OR you could simply ask your tiler to buy them at trade for you and put them on the wall for you. (this shouldn't be a big job it doesn't take long and you dont have to be particularly accurate).

This is just my tip for making a bathroom warmer and this is a guess but im sure over time it would pay for itself keeping the house as a whole warmer.

ilikecookies wrote: »

Looking for a bit of advice around insulating above and beyond the normal measures.

The context is as follows - we live in a 1950s 5-bed house, off-grid, in a fairly exposed location. Since moving here 3 years ago we've done the more obvious insulation measures: double-glazing, loft insulation and cavity wall. That said the house still feels cold and I think heat retention is poor.

As a result we burn through a lot of oil: 2500 litres/year which might not sound much for a 5-bed but that's generally only providing 5 hours of heating a day in the winter months at a setpoint of around 19.5 degrees (ie. not tropical by any means).

In the future we plan to carry out a fair bit of work on the property. I'm wondering what additional insulation measures we could look at. Cost will be an issue (isn't it always!) but at this point I'd like to get all the options on the table and go from there.

3 big measures I thought of were:

1) Insulating internally any external walls. For example using aerogel board and then decorating over that. I guess my only concern with this approach is ensuring there is adequate air flow/ventilation through the walls to prevent damp given that we already have cavity wall insulation.

2) In the loft we have the loft-floor (between the joists) insulated. Should we look at insulating up above (ie. between the rafters)? Again I wonder how to control the moisture.

3) Simply oversizing the heating system to a ridiculous degree! Sure the running costs will be high but these may be on a par with the cost of retrofitting additional insulation!

I imagine option 1 will be rather expensive and time-consuming but will have the biggest pay-off long-term.

But then again maybe I should start with one of these heat-loss surveys (using a sensing camera) as maybe the areas of biggest heat-loss are not where I think. For example, the problems might relate to a poorly insulated floor which will be pretty hard/expensive to retro-fix.

Any advice appreciated!

new_owner

ilikecookies wrote: »

2) In the loft we have the loft-floor (between the joists) insulated. Should we look at insulating up above (ie. between the rafters)? Again I wonder how to control the moisture.

You should have a minimum of 300mm of loft insulation. Rase the flooring and add more insulation will be a cheap solution. With the price of insulation and as this is something you can do your self, I would (have) add up to 500mm of insulation.

Builders paper or other vapor barrier should be fine.

I would not recommend insulating rafters unless its to be used as a room.

Unless it already is a room?

[Deleted User]

we lived in one house where we had exterior insulation installed ie all around the house, it was effective

We now live in an eco house and besides the outstanding levels of insulation we have a heat sink floor (thick tiles) and an interior heat sink wall just behind the stove. They release stored heat slowly in winter and keep the house at pretty constant temperature. The only heating for house and water comes from the stove at this time of year. 4 bed detached and we use just 8 kg of wood pellets a day at the moment. It will need a max of 10 kg a day if the weather deteriorates a lot

reeac

ilikecookies wrote: »

Looking for a bit of advice around insulating above and beyond the normal measures.

The context is as follows - we live in a 1950s 5-bed house, off-grid, in a fairly exposed location. Since moving here 3 years ago we've done the more obvious insulation measures: double-glazing, loft insulation and cavity wall.

But then again maybe I should start with one of these heat-loss surveys (using a sensing camera) as maybe the areas of biggest heat-loss are not where I think. For example, the problems might relate to a poorly insulated floor which will be pretty hard/expensive to retro-fix.

Any advice appreciated!

Underfloor insulation is mandatory nowadays for new houses. Particularly effective if you have suspended timber floors but very disruptive to install. An easy alternative is thick carpets.

ilikecookies

Thanks to all for the comments so far. A couple of comments:

malc_b - thanks for the tip RE working out heat losses. Will definitely check this out. You're right that I should run the heating longer. I guess it's a bit chicken and egg though as I sometimes think if I'm not retaining the heat well what's the point! But I might be being unrealistic about how much heat I should expect to retain. I'll have to get my heat around the heat debt idea. Isn't this an argument to keep the heating on 24 hours to eliminate the need for refiring, reheating from cold, etc.

Nifty-thrifty - that's exactly the sort of thing I had in mind. I assume as you've retro-fitted this to a bathroom you didn't have to worry about ventilation per se as you may already have a extractor, etc?

New_owner - I think we have 300mm. Not sure if I can get much more in as its reached the level of the joists and it's useful to be able to see these when we go into the loft. Not using it as a room at the minute but I was just wondering if insulating in the rafters was a possibility to enhance what we have but reading between the lines the gains of doing this will be minimal given the existing insulation in there.

kittie - your house sounds like my dream! I particularly like the passive-house concept but these are pretty rare unless you build one yourself!

reeac - I think thick underlay and a thick carpet will be the order of the day when we replace these as I can't see how downstairs (where we have concerete throughout) that much can be done.

Thanks to all again. More suggestions appreciated!

southernscouser

Not an expert by any means but my understanding is windows are the biggest source of heat loss.

How efficient is your double glazing? Any blown panels? Are the beadings a tight fit?

Is triple glazing a financially viable option?

Do you have any thick curtains for the windows or do you have blinds? (not sure how effective they are for heat retention but just throwing ideas about).

malc_b

ilikecookies wrote: »

Thanks to all for the comments so far. A couple of comments:

malc_b - thanks for the tip RE working out heat losses. Will definitely check this out. You're right that I should run the heating longer. I guess it's a bit chicken and egg though as I sometimes think if I'm not retaining the heat well what's the point! But I might be being unrealistic about how much heat I should expect to retain. I'll have to get my heat around the heat debt idea. Isn't this an argument to keep the heating on 24 hours to eliminate the need for refiring, reheating from cold, etc.

reeac - I think thick underlay and a thick carpet will be the order of the day when we replace these as I can't see how downstairs (where we have concerete throughout) that much can be done.

24hr heating is a maybe. Turning the CH off overnight for example, means the average temperature in the house drops so the total loss per 24hrs drops. But you then have to work the heating harder during the 16hrs on. Since the saving by turning off overnight is similar to the difference between condensing and non condensing mode then it may well be a fuel saving to run 24hr even though the house is losing more heat. Certainly some people in the thread on 24hr heating "myth" report they find it cheaper to run 24hr which could well be because then the run continuously on condensing mode. You're even more extreme since you only run for 5hrs.

If you want thick underlay they I'd suggest looking on the net as what costs 6/7 quid in carpet shops is 2/3 quid ordered online. Modern underlays are warmer than the old rubber waffle type.

Ken68

Hi cookie...I have removeable window shutters made from polystyrene (put up in the evening and down in the morning).Light weight and only on those windows downstairs at the back of the house, these being to the north.
A remote thermometer gun shows the same heat emmissions as the walls, so I know they work.
The panels were given to me courtesy of my former neighbour who was in the flat roof business, so no cost to me other than taping the edges. Might be worth doing with one sheet of Celotex to try or even the cheapest 50mm polystyrene.
Your windows must have enough space to take the material.

malc_b

Another thought. You mention you're in an exposed position and I remember reading this

http://www.askjeff.co.uk/cavity.html

which reckons that cavity wall insulation is not recommend in exposed positions because you then get damp coming through. I wonder if your high bills and cold house is due to the walls being damp and so not insulation like they should? So maybe what you need is a layer to stop the damp getting into the outer brick? If the house painted and all the mortar joints are ok then that should stop the damp. Or for plain brick you can get a clear coating then soaks into the bricks and makes them waterproof (I can't remember the name of the one I saw but a quick google found Thompsons Waterseal and Feb silicone waterproofer).