Ways to reduce utility bills and make home energy efficient

[noseall]

We were talking about internal walls.

But if you want to talk about external walls, then a thermal mass (read: heavy masonry), with external insulation, reduces the need for said external insulation, meaning it is more effective than just a insulated external wall.

Insulation is important (on external walls) regardless of position.
Other things to consider are the heating, passage of vapour, windows, roof overhang, economy etc when determining the optimum position for the Insulation.

 

[Harry Bloomfield]

So does insulation, it's effectiveness and cost savings

Insulation cannot (heat) or cool a room down, a cooler than the room thermal mass can.

 

[wobs]

Insulation is important (on external walls) regardless of position.
Other things to consider are the heating, passage of vapour, windows, roof overhang, economy etc when determining the optimum position for the Insulation.

All else being equal, you can get better thermal performance with as thermnal mass with insulation on the outside. You need far less insulation for the same thermal performance.

 

[Bod ...]

Done just that... in doing my Kitchen I have insulated 2 externals walls in my kitchen and 1 in my living room.

Also in doing my Kitchen I have replaced all the 15mm hot feeds to

taps with 10mm feeds and insulated them from a manifold.

Next year I'll insulate the spare room and hopefully fit triple glazing.View attachment 284297

Insulated all pipework I can get to. Hot & Cold + the heating pipes.

 

[jeds]

All else being equal, you can get better thermal performance with as thermnal mass with insulation on the outside. You need far less insulation for the same thermal performance.

That's not correct. Moving the insulation layer from internal to external produces exactly the same u-value for the same materials. What changes is the thermal response and by far the most efficient is that which provides the fastest thermal response - and that is having the insulation closest to the source of the heat. Heat when you need it, not when you don't. Thermal mass will inevitably heat spaces when you don't benefit from it.

 

[wobs]

That's not correct. Moving the insulation layer from internal to external produces exactly the same u-value for the same materials. What changes is the thermal response and by far the most efficient is that which provides the fastest thermal response - and that is having the insulation closest to the source of the heat. Heat when you need it, not when you don't. Thermal mass will inevitably heat spaces when you don't benefit from it.

You misunderstand the issue. You get a more overall efficient house if you can have external insulation rather than internal, as the thermal mass of the masonry provides a thermal mass. MikeG explains it better than I could on another forum:

I did two theses on low energy buildings in temperate climates, so I can bore for England on this subject. Many years ago I built a side-by-side experiment with a pair of very similar houses, one of which was a lightweight super-insulated structure (double-stud walls with 300mm mineral wool, 450mm ins in loft, triple glazed, ventilation system with heat recovery), and the other with a similar construction to what I am doing here. The heavyweight house performed better in all respects: less prone to overheating, much more stable internal temperature, 30% more fuel-efficient......and that despite having 33% less insulation in the walls. I also extrapolated the results to very hot and very cold climates, and came to the conclusion that the heavyweight construction would still outperform the lightweight so long as the insulation was thick enough, and of course, provided the ventilation heat/ coolth losses were controlled. I'm sure someone will have built actual examples to test this in harsher climates, but I haven't seen anything.

As for how the masses are actually calculated: well, I haven't got an academic reference, but I do know that the guy who knows more about this than probably anyone in the world has just built himself a cast in-situ concrete house..........8" thick solid walls, ground floor, first floor, ceiling to first floor........all solid concrete.....and then massively externally insulated it. He has provided no heat source whatsoever, other than an external sun-space (conservatory), and stays above 22C all day, all night, all winter, solely from "waste" heat from lighting, cooking, and the big two....the fridge, and the hot water system. Controlling the inputs from the conservatory is automatic and easy. Bear in mind that a human body gives off about a kilowatt, so also makes a big contribution to the tiny heat requirements of a building like that. He told me that there is no way in this country of having too much thermal mass.

If you're wondering who this is, he is an architect who renovated a cottage and showed it in great detail here:

TheWoodHaven2 • View topic - Mike's extension & renovation (Sunroom....rafter)

thewoodhaven2.co.uk

 

[Justin Passing]

When I see internal insulation I 'm remnded of a couple of cases of trouble where the warm damp air got past it and rotted things in the fabric of the building. Fiding, and promoting, a cold spot.

by far the most efficient is that which provides the fastest thermal response

Not with you there. You want a thermal NON response!
Outside temp changes, but inside, nothing. You don't need the wall heating up and cooling down with the weather.

 

[jeds]

This is purely to do with heat loss, which is measured by thermal transmittance - or u-value - of the material layers. Changing the position of the mass and insulation layers makes no difference to the u-value. The most efficient (most controllable) model is where the space heats quickly in response to heat input. Leaving the heating on 24 hours and 'warming the walls' is outdated thinking.

 

[wobs]

This is purely to do with heat loss, which is measured by thermal transmittance - or u-value - of the material layers. Changing the position of the mass and insulation layers makes no difference to the u-value.

I'm aware that the u-value doesn't change.

The most efficient (most controllable) model is where the space heats quickly in response to heat input. Leaving the heating on 24 hours and 'warming the walls' is outdated thinking.

I am not suggesting you keep the heating on all the time. In fact leaving the heating on 24hr is the opposite to what I am saying.
Its about using the thermal mass to release heat back into the house after the heating has gone off. The experiment above shows that this is a more efficient use of materials than having insulation on the inside of the walls or a light wooden frame.

The above quote clearly says "30% more fuel-efficient......and that despite having 33% less insulation in the walls."

 

[JP_]

Why would you insulate internal walls? (Assuming masonry walls). If they are hollow, then they an act as thermal funnels in certain circumstances.

But if masonry, they act as thermal stores.

sorry, internally insulate walls. Cheaper than external.

 

[Deleted member 18243]

I do a similar thing when I'm boiling eggs. I bring them to the boil, cover with a lid, turn the heat off and, after ten minutes they are nicely boiled.

Delia Smith demonstrated this on one of her programmes in the 70s (or 80s?) and I've used the method ever since.

cost of living crisis

Cost of covid crisis.

This Autumn has been very mild....

The £66 the government put in our account has meant our G&E bill was only £13 last month.

My G&E bill was zero because of this. What a fool's paradise our leaders have created!

 

[JP_]

Cost of covid crisis.

Doesn't matter what your politics is, everything is still more expensive.

 

[securespark]

I find when I cook, it creates enough of a rise in temperature to heat the room (5 x 5m) comfortably.

I plan also to ban use of the tumble dryer and put our heated drying rack in the lounge to heat that room.

I'd like to get a wood burner, but Mrs Secure is worried about exacerbating Asthma.

 

[JohnD]

I plan also to ban use of the tumble dryer and put our heated drying rack in the lounge to heat that room.

And humidify it

 

[securespark]

We don't have any issues in that regard. The heated rack has been used in the next room for many years and not resulted in any decay.