Water based underfloor heating

highrisklowreturn

Pincher wrote: »

The UFH temperature is restricted by a separate thermostatic mixer. When you are heating up from cold, you might get 70 degrees from the boiler, because the boiler thinks the house is too cold and needs to go full blast, but only some of the boiler output is mixed with the UFH loop, with the rest "rejected" because it's TOO HOT. The consequence you get NO CONDENSATION.

My Glowworm setup is geared towards temperature maintenance, with weather compensation as well, so there is no need to go full blast. The boiler output is around 50 degrees C, so the UFH mixer won't reject most of it. The returning water is cooler, so condensation happens most of the time.

When it's 0 degrees outside, like today, I spend £10~£12 on gas a day, maintaining 20 degrees, for a 5 bed semi, which is about right. When you say 40% is spent on the kitchen UFH with everything else switched off, you are still heating the rest of the house, because heat spreads and rises. If the overall heating cost is about right for your house, I wouldn't worry about it.

My kitchen floor gets toasty in 30 minutes, and I can definitely feel it through socks. We dug up the concrete, put in 100mm of Kingspan, pegged the pipes directly on the Kingspan, then about 30mm of scree (cement), then glue and tiles. Only exposed floor area have UFH, not under kitchen units, and CERTAINLY not under the freezer. So in a 14m2 kitchen, only 7m2 of UFH.

1. Is the thermostatic mixer temperature set TOO LOW?

2. Is the UFH pump speed set to LOW (I/II/III)?

3. Pipe run too long. maximum length 100 meter per loop.

For a double bedroom, of 24m2, we needed two loops. For 32m2, I would expect you have three loops.

My kitchen floor does not actually use a separate pump.
The length of the pipe introduces quite a lot of resistance, such that the flow is relatively slow, so that the exit end of the floor is noticeably cooler than the entry end. I have a wall TRV (high mounted, not near ground level, which will pickup the heat from the floor and close the valve prematurely) which allows me to control the flow, but I leave it on maximum, because the flow is slow enough already.

4. Insufficient insulation, so you are heating the concrete first.

My floor cools down in 30 minutes, because the scree is the only thermal mass. If yours takes hours to cool down, I suspect the entire "suspended concrete floor" is the thermal mass.

This exemplifies exactly what I mean - imagine spending £300 to heat a house, mate stick a fire in, and £2 a day on coal will keep you warm, happy, and unite your family around a common focus point. Or waste cash keeping up appearances.

reeac

highrisklowreturn wrote: »

Buy a superser. Pay £17 for a bottle which last 2-3weeks Problem solved.

I don't even understand why people pay for central heating - if I had a new build I would keep it totally out, have a stove, superser, and an electric feed to the bathroom water - or spend thousands on a system that might need replaced, swapped between oil and gas, develop leaks in hard to reach places, rust, get gunked up and 'need' 'power flushed' every time a radiator won't heat.

How people heat their houses today is mental - 100 years ago people would have 10 kids and have them around one or two house fires and that would do it.

Like the 4 Yorkshiremen ... although they didn't have the fires.