Insulation................absolutely wonderful stuff...........

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.............n there's a million facts n figures to support it n given the choice, I would live in a brick house with 24" walls, 12" of which would be polystyrene, but that aint gonna happen. So, lets say I have a modern house insulated to the latest standards with a gas boiler n radiators. Will the house lose 20/30/40% of the heat being pumped into it?
 
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Yes, silly me, my question is nothing more than theoretical, so perhaps I should ask it another way, a modern home to the latest insulation spec will lose heat much slower than it's victorian equivalent, but how much slower 50% 80% 20%?
 
Well if you google something like “typical U values” you’ll find examples such as

Solid brick wall, 2 W/m^2K
Insulated wall, 0.18 W/m^2K

So you would lose 10 times less heat through the wall - if you kept the internal temperature the same.

Numbers for a whole house are complicated, and every building is different. And in reality, people don’t “save” the energy when they add insulation, they just live in a warmer house.
 
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I'm happy with U n R values but the W/m thing is waay too clever for lil' ol' me.
losing 10 times less heat is therefore a 1000% improvement
If heat isn't gettin sucked through the walls/floor. ceilings, the stat will switch the boiler off more often n so the owner will use less gas
 
.............n there's a million facts n figures to support it n given the choice, I would live in a brick house with 24" walls, 12" of which would be polystyrene, but that aint gonna happen. So, lets say I have a modern house insulated to the latest standards with a gas boiler n radiators. Will the house lose 20/30/40% of the heat being pumped into it?
To be unhelpful, it will have to lose all the heat pumped into it eventually. If you keep pumping more heat in than can escape eventually the house will eventually get so hot it melts into magma and plasma.

The other possibly unhelpful metric would be the passive House standard, which effectively means no dedicated heating system is required (just MHRV). Apparently that involves a 75% reduction of heat loss compared to the current building standard.

If you wanted a comparison in real terms have a look at the comparison charts you find on places like the energy saving trust saying how much you'd spend or save depending on improvements made to single brick.
 
It is also made more complicated by solar gain and thermal store.

Most modern highly insulated houses have the insulation on the inside, with no energy absorbing materials on the warm side.

That may work well for working people, who come home and whack the heating on and want the house to heat up fast.

Somebody that spends most of the day at home might benefit from a house with concrete walls inside the insulation....that absorbs heat and releases it slowly. These houses also stay cooler in summer.

Solar gain can help if sunlight heats say a screed floor.
 
Solar gain is a two edged sword, nice in the winter................dreadful in the summer..........better to try n limit it with insulation.

Thermal store is great for internal walls n floors as they'll act like radiators, but external walls would surely just be heat sinks
 
To be unhelpful, it will have to lose all the heat pumped into it eventually. If you keep pumping more heat in than can escape eventually the house will eventually get so hot it melts into magma and plasma.
Not that simple.
The loss of heat is not a straight line proportion to the difference in the temperature outside and temperature inside.
As the differentiation in temperature increases the rate of loss increases.
 
Not that simple.
The loss of heat is not a straight line proportion to the difference in the temperature outside and temperature inside.
As the differentiation in temperature increases the rate of loss increases.
Yes that simple, if an object is gaining heat faster than it loses it then it goes up in temperature. You're saying that at some point it'll reach equilibrium, which wasn't part of the brief. It's a silly point, but that's physics for you, full of perfect spheres on frictionless planes.
 
Yes that simple, if an object is gaining heat faster than it loses it then it goes up in temperature. You're saying that at some point it'll reach equilibrium, which wasn't part of the brief. It's a silly point, but that's physics for you, full of perfect spheres on frictionless planes.
Not at all. I'm saying the greater the differential, the faster the heat loss. Thus, as the temperature inside increases, the heat loss will accelerate, assuming the temperature remains reasonably constant outside.

 

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