Improve insulation or move house?

[NChouseinsulation]

I'd love your views, especially if you have first hand experience of this...

I'm weighing up whether to (a) improve insulation of existing property (£4.5k?) or (b) move house (£19k?).

What would you do / what have you done in similar circumstances?

The details, if you want them:

(a) Existing property
1920s semi
Insulated loft, fully double glazed
No cavity wall.
20 year old boiler with hot water tank still going strong
Combined gas/elec bill about £75 per month
Great location, great street, unclear how noisy my new adjoining neighbour will be
Nice size, good parking, now decorated to my taste

I'm considering:

• underfloor insulation of the ground floor, hoping it will increase comfort and speed of house heating up. Will be just the suspended floorboard areas (80% of house?) not the 1990s extension concrete floors (20%?). The payback period (installation cost v future gas bill savings) is much more than the recommended 5 to 10 years. Quotes are about £1400 (will wreck floorboards, so add £1000 resanding cost to that) and about £4500 (will not need resanding and is my preferred option). Neither uses spray on foam, they use fibre slung in nets. I'm not eligible for grants. I'm not keen to DIY - floor void expected to be reasonably shallow and nervous about accidentally blocking airbricks. I will contact Building Control to be sure what insulation I am / am not allowed to have installed.
• insulating walls is less likely as internal insulation loses too much room size and would require redecorating. External wall insulation may be £13k, though I've not asked for quote yet. I'm reluctant due to cost and change in external appearance of house, especially as will look odd next to adjoining semi.
• unlikely to replace boiler until it dies as GasSafe engineer advises a couple of years ago that it will make little difference on heating costs, I didn't ask about comfort levels

(b) Move house
Ideally to a modern, detached house to get better insulation and no adjoining neighbour
If lucky enough to find such a house for similar value to existing house... moving cost is in the ballpark of £19k based on:
Stamp duty: £8k
Solicitors fees: 2x £1.5k
Estate agent fees: £6k?
Survey? £0.5k
Mortgage fee for new set up, if cannot port: £1k
Furniture removal £0.5k

So, while underfloor insulation is not deemed to be cost effective on the normal calculation of number of years to recoup cost, it is much cheaper than moving house, even if I've overestimated the moving house costs.

After extensive Internet searching (Energy Saving Trust, Superhomes, various other sites), I'd love to hear someone's first hand experience.

Thank you.

I would move purely to be detached even if detached house had less insulation!

Do you have bare floorboards on the ground floor?

Do you leave the interior doors open, or have an open-plan layout?

If you have a 20-year old boiler and cylinder, is it an iron boiler? Or condensing?

Why do you want to spend money without a good return on investment?

Thanks PigletJohn

Q: Do you have bare floorboards on the ground floor?
A: Bare floorboards mainly. 1 room has large rug. Kitchen has amtico tiles. Keen to keep bare floorboards even though carpet has insulating benefits.

Q: Do you leave the interior doors open, or have an open-plan layout?
A: Not open plan. Separate rooms. I vary on remembering to close doors.

Q: If you have a 20-year old boiler and cylinder, is it an iron boiler? Or condensing?
A: Not condensing, so I assume iron.

Q: Why do you want to spend money without a good return on investment?
A: I want to improve my comfort levels and hopefully reduce environmental impact. It takes 4+ hours to heat house in winter, so often cool/cold as my getting home time after work is rather unpredictable between 6pm and 10pm. Not keen to waste money. It didn't feel cost effective to improve existing home, but moving appears to be even less cost effective, which makes improving more tempting than I thought.

If you move from an iron to a condensing boiler, and a modern, better insulated (preferably unvented) cylinder, and insulate the hot pipes, you might see a 20% reduction in gas usage (mine dropped by more than that). A combi is a bit less economical, especially on the summer usage.

If your house is slow to heat, you can increase the radiator sizes. Old heating systems were often designed to be rather meagre. If you state a few room sizes and radiator sizes I can make a guess. There might perhaps be some sediment blockage or balancing errors.

Are the existing radiators fully hot, all over, sides, centre, top and bottom, within half an hour of putting the heating on? The flow (incoming) water pipe should be "too hot to hold" and the "return" water pipe on the other end of the radiator should be "too hot to hold for long."

@PigletJohn. Interested what you say about the boiler. We have one boiler that is 20 years old. 30kw boiler and is fine but BG has been trying to persuade us for 9 years to change it as parts out of availability. Actually it is only stuff like a casing or heat exchanger that is out of supply. It is a unvented system with reasonably modern hot water cylinder and seems to work fine. What would you think we would save by changing it to condensing? Gas bill is circa £1300 pa..

Sorry for hijacking your thread OP

Some people say that BG unaccountably finds some parts unobtainable that a small independent can find.

I indicated a possible gas saving above. a 20 year old boiler might be condensing.

My old iron boiler had an efficiency rating of 65.0% which is particularly bad.

You can look up efficiencies of old boilers. Look for "'Seasonal Efficiency of a Domestic Boiler in the UK" or "SEDBUK" Make sure your internet security package is up to date because apparently there are some rogue websites.

@PigletJohn . It isn't condensing and I understand is about 80% efficiency. (Gloworm). I'm loath to change it to be honest. I assume then that the additional 15% would save me £90 per annum then

@PigletJohn

Hi Piglet John. Thank you for your second reply. You are being very helpful.

My boiler is 76% efficient and I confirm it is non-condensing, Gloworm Ultimate 50ff which my reliable and trustworthy GasSafe engineer recommends keeping for as long as possible. (So, similar efficiency to @MarieG10)

The radiators heat up fully within 30 minutes. They all have TRVs. The pipe at the TRV end is almost too hot to handle and the pipe at the other end can only be held for a short while.

Here are the room and radiator sizes. Ceiling height is 2.4m. The rooms were renovated at different times over the last maybe 30 years, so radiator choices are probably not consistent. I list them all, absolutely not thinking you'll comment on them all. Instead, please take your pick.

Downstairs
Hall: 4.1 x 1.9m, radiator 74 x 96cm, single with fins. Main thermostat is in this room. 2 external walls, brick, probably 22cm, definitely no cavity.
Living room: 3.7 x 3.7m, radiator 44 x 128cm, double with fins. 1 external wall, brick, probably 22cm, definitely no cavity, approx. 40% of the external wall is a double glazed (DG) window.
Dining room: 3.3 x 5.9m, radiator 1 in original part of house is 44 x 192cm, single with fins, radiator 2 in extension part of house is 45 x 108cm, single with fins. Room is one room, no wall or door between the original and extension parts. 1 external wall, probably has cavity as mid-1990s, approx. 50% of this wall is DG window. 2.25m of the length is the 1990s extension.
Kitchen: 4.7 x 2.3m, radiator 180 x 50cm, single, no fins, installed in last 3 years, approx. 1042W or 3555 BTU. Higher BTU than room needs, so kept on lowish. 2 external walls, long wall is brick, probably 22cm, definitely no cavity, short wall probably has cavity as mid-1990s, approx. 70% of this wall is DG window. 2.25m of the length is the 1990s extension.

Upstairs
Bathroom: 2.2 x 2.6m, towel rail 180 x 60cm, installed in last 10 years, approx. 852W or 2905 BTU. Higher BTU than room needs, so kept on lowish. Boiler is in this room. 2 external walls. Approx. 40% of 1 wall is DG window.
Bedroom 1: 3.7 x 3.2m, radiator 60 x 112cm, single with fins. 1 external wall, brick, probably 22cm, definitely no cavity. Approx. 40% of this wall is DG window.
Bedroom 2: 3.5 x 3.3m, radiator 43 x 128 cm, single with fins. 1 external wall, brick, probably 22cm, definitely no cavity. Approx. 40% of this wall is DG window.
Bedroom 3: 2.2 x 2.6m, radiator 60 x 60 cm, single with fins. 2 external walls, brick, probably 22cm, definitely no cavity. Approx. 40% of 1 wall is DG window.

Thank for your useful comments. I considered my radiator suitability a few years ago, and can’t remember the details. The conclusion must have been not to change them (or not yet). Good to think about this again.

Your downstairs rads look OK, apart from the living room, but the others look too small. The room with bare boards will get a certain amount of cold draught, making your feet cold. If the room door is left open, the cold air will enable the warm to flow away through the doorway (or fireplace, if open).

First clue: they are fully hot but take a long time to heat the room, therefore they are too small

Second clue: measurements, look too small for a house without CWI.

Bigger rads will heat the rooms quicker, then the TRVs will prevent the rooms getting too hot. Bigger rads, running warm, keep a room at a more even and comfortable temperature (wide, low ones are better for this than short tall ones). A long room benefits from a rad at each end. Modern practice is to put the room stat in your main living room, with no TRVs, and to balance the radiators so that room heats up slower than all the others.

Have a look at the thickness of the loft insulation. 100mm is quite good, and used to be standard, but modern houses have 250mm/300mm (this is a problem if you want to walk or store anything in the loft, but it can be done). The incremental value over 200mm is not much (this is easier to floor over).

@PigletJohn

Great, thank you. I'll look into increasing some of the radiators, and check tje balancing.

Interestingly, the room stat was in the dining room until a month ago when a relative encouraged me to put it in the hall. It's now back in the dining room (the room that gets used the most).

Loft insulation is 20/25 cm laid on top of the boards, and whatever is under the boards. So, sounds adequate.

I appreciate all your information and tips. I think you've given me the solution without crazy expense.