Under floor heating with piped water system

Cardew

Mickey666 said:

1. UFH runs at a lower temperature because the surface are of the ‘radiator’, ie the floor itself, is very large.  If wall-hung metal Radiators were just as large then they could be run cooler as well for the same heating effect. Nothing to do with condensing boilers.  Basic physics dictates that a certain room volume with certain insulation properties will require the same energy (heat) input to maintain a given temperature regardless of the energy source.

It has everything to do with condensing boilers! Condensing boilers run more efficiently at low water temperatures. That is why the more sophisticated  central heating boilers have a weather compensating network to lower the water temperature whenever possible and increase efficiency.

Of course if you had radiators as large as the 'floor itself' the water temperature could be lower and and efficiency increased - you are confirming the point OVO were  making in their link.

As for 'basic physics' naturally a room will require the same energy input to maintain a given temperature. However your statement 'regardless of energy source' completely misses the point.  The cost of delivering that energy was the issue. - and the statement made in the link simply made that point.

The ability of a boiler to operate more efficiently producing the low temperature water for underfloor heating means that it could reduce the cost of heating compared to radiators. 

Mickey666

I think we're at crossed purposes.  Energy efficiency and the cost of energy are two different things.  For example, an electric boiler is far more efficient than even a condensing gas boiler but I think we both know which will be cheaper to run.

Cardew

Mickey666 said:

I think we're at crossed purposes.  Energy efficiency and the cost of energy are two different things.  For example, an electric boiler is far more efficient than even a condensing gas boiler but I think we both know which will be cheaper to run.

Energy efficiency affects the cost of energy when the source is the same boiler

I was merely agreeing with the OVO comment that stated

'A suitably sized unit can heat a larger area than an individual radiator, and works at a lower temperature, so it could reduce your heating bills'

Maz1963

Thanks. All useful info. I think each room will have a separate thermostat, but it will all be explained to me when I go back for the post reservation review.  I am sure the house will be super insulated as a new build, and there are solar panels on the roof to produce some electricity (though not set up to feed back and offset, etc.). I am expecting to vastly reduce my energy bills over the current property, which is an old house and costs a small fortune to warm up. I am also not a lover of excessive heat, so my thermostat rarely goes above 19 in the winter - the mention of a heat setting of 21 degrees in the house makes me shudder!  None of the new builds I looked at had a condensing gas boiler. This one has a gas boiler with a hot water tank.  I don't know why that is.  I currently have a condensing boiler and it's great, until two people get into the shower at the same time!  Maybe that's why they are not much used in new builds?
It was really interesting seeing all the different types of boilers etc in the new builds I viewed. Some had an LPG gas supply and a few had an air source heat pump (which I didn't realise had a huge unit sitting outside the house!). But I've ended up with gas, underfloor piped water heating, rads upstairs, plus solar panels. It will be interesting to see how it all works and how costs compare to current house

matelodave

You are confusing a condensing boiler with a combi boiler.

A combi doesn't have a hot water tank but you'll be hard pushed nowadays to get any sort of gas boiler that's not "condensing" whether it be a system boiler (with a tank) or a combi (without one). Condensing is the way the boiler operates to recover as much heat as possible from the fuel burned to the point where the flue gases condense within the boiler and it's necessary to drain the condensate via a waste pipe and the exhaust gas tends to look like steam (pluming)

Maz1963

matelodave said:

You are confusing a condensing boiler with a combi boiler.

A combi doesn't have a hot water tank but you'll be hard pushed nowadays to get any sort of gas boiler that's not "condensing" whether it be a system boiler (with a tank) or a combi (without one). Condensing is the way the boiler operates to recover as much heat as possible from the fuel burned to the point where the flue gases condense within the boiler and it's necessary to drain the condensate via a waste pipe and the exhaust gas tends to look like steam (pluming)

You're absolutely right, I am! You're getting a bit technical now, but I think I understand the difference.  What I meant to say is that the new builds I looked at all had a hot water tank, which surprised me, as I assumed combi is the way to go - more efficient and no need for the tank.  I currently have a Worcester Bosch, Greenstar I think, which I believe is a combi and condenses?!  There is no tank and I have the condensate pipe and yes, the pluming as well.  The person who installed the original boiler put a narrow condensate pipe in and one winter it froze up and messed up the boiler! Got that sorted though when the new one was installed.
If I was confused about combi and condensing, I'll have to concentrate when they explain the new house to me!  With the solar panel controls, a box with all the pipes linking in for the underfloor heating, hot water tank controls and all the related thermostats, I might have to go on a course.

Talldave

How intimidating it is depends on whether it's been set up right. Last year my partner rented a new build "cottage" for work and the UFH didn’t work. Despite the builders coming back and tinkering for ages, the end result was just a hot cupboard where the boiler was, as it was running constantly because the room stats were endlessly calling for heat and none was forthcoming. I spent hours reading up on UFH and eventually realised that the flow adjusters on the manifold were all shut off. After a nervous session of twiddling things, the pipes magically got hot and by the next day the place was toasty warm!!

When you work out how it all works it is all rather straightforward,  it just looks intimidating because of the manifold, actuators, controller and valves.

The important lesson,  to avoid a cold night in winter, is to learn how to top up the  boiler pressure using the fill loop and check it every few weeks. Because when the pressure drops, the boiler just sulks and you need to know how to reset it as well.