Underfloor heating

[IMM]

ROFL, ROLF. My, my. Just like Last of The Summers Wine. ROFL!

[John Armstrong]

I would rather not be in a room where the air is hotter than my body temperature thank you very much.

[IMM]

Then be in cold room then. No accounting for odd tastes.

[Peter Parry]

He has a Bachelor of Science in mechanical engineering and majored in HVAC. Your qualifications are what exactly?

If you think it is inaccurate please explain how the surfaces in a room can have a temperature greater than the air temperature with a blown air system.

To never more than the air temperature and for exterior walls usually less.

I don't think you really understand it at all. How does insulation help?

I can certainly see that.

I agree, it does matter quite a lot doesn't it.

I see, you have no idea if you will be returning to the house at all, if it will be at 10:00, 13:00, 17:00, 20:00. Each day is totally new

- some you are in all day - others out day and night. I suppose being an emergency plumber does have its down side.

Do the sums. The difference is not terrible great.

That doesn't leave much else to make a living with.

If I understood what you were trying to say I might be able to comment.

Oh dear.

Only in catalogue land. The great advantage of slow reaction systems is the controls can be really simple _if_ the design is right in the first place. If on the other hand the designer doesn't believe in physics then I agree more complex controls will compensate to some extent for the basic design errors they will make.

I have never had to add to the heating but have certainly had one or two days in the year where we have opened a window or two. It doesn't detract from the overall comfort of the system for the remaining 363 days of the year.

It s been a "fad" for the last 15 years at least. (actually the last

2000 odd to be more precise)

And you have experienced ?

An assortment of far better qualified people than you including engineers (not fitters) from the manufacturers have said it is well designed and installed.

I was suggesting a more appropriate heating system for people who cannot add 3 to another number and come up with the correct answer.

[Peter Parry]

Anywhere - as long as you get one.

[John Armstrong]

20 deg or so is fine for me. Living in a room hot enough to cause heat stroke is definitely an odd taste.

[SC]

"SC" wrote

Phew I've started World War III!! But it has brought out a lot of good points.

To summerise: People like underfloor heating, but it needs to be put down well. Issues to consider: are heatup time lag (the changeable Autumn/Spring weather point was good), avoid hotspots, good underfloor insulation, separate controller at boiler, no radiator to hang your wet socks (sorry this is important to me). Good things are: a comfortable heat at lower temps, warm bare toes, radiators not hogging wall space, cosy warm floor for kiddies to roll on, overall lower cost in my situation.

My situation is: this is for a large L-shaped room 20'x20' which will be kitchen/ dining/ living space. Ventilation/ heating are very important as we are combining a cooking and living environment. I only work mornings, home with after school childcare and quite often have to be up at night with wains, so always on heating is fine. The back door will open into a sunroom part of this area - draughts when the door is opened, plus condensation from kitchen activity on sunroom windows.

My experience was of being brought up in a 200yr old farmhouse with only an Rayburn Royal for heat, or open the airing cupboard in the bathroom to take the chill of an enamal bath. Consequently I can stand too much heat, and especially heat convection/hot air heaters. Turns me into a heat hogging zombie with red legs.

What I think maybe good for us will be a separate controller for UF to the combi (located just off this room) and a good control for settings. I will not run the UF round the cooking and dishwasher/ sink area as I would overheat. In addition I will run a slim radiator round under the windows in the sunroom as this will be the coldest area, most prone to condensation, and also give me somewhere to warm socks towels etc.

Whadda think??

NO scrapping boys

Ta Suzanne

[SC]

Don't get a job in Iraq then. Did you see they had 50 C??? How could you hack that? It's 22C here tonight and I'm boiled.

[Owain]

"Peter Parry" wrote | >I needed heat ASAP when I walked in, not having the heating system | >needlessly on just in case. That is wasteful. | I see, you have no idea if you will be returning to the house at all, | if it will be at 10:00, 13:00, 17:00, 20:00. Each day is totally new | - some you are in all day - others out day and night. I suppose | being an emergency plumber does have its down side.

But an emergency plumber could afford to run the heating all day, the rates they charge.

Owain

[SC]

You're missing the point. Body temperature is 37C ish. Comfortable room temperature is between 18 and 21C. I know this because I work in a large open plan office and sit beside the control. There is a constant battle between different people jacking the heat and turning it down. So much so the management brought in some bozo specialist to sort the whole thing out. Hasn't made a blind bit of difference. The bit I sit at is colder and that suits me just fine, especially since I have been pregnant 2 and quarter years in the last 5.

You know, thats the warmest kind of heating you can have. Another entity hatching inside you. And you boyos can't argue on that....

Suzanne

[IMM]

One certainly could. I couldn't.

[IMM]

I lived over there for a while. The dry heat makes it bearable. You get used to it.

[Peter Parry]

Go on - don't be shy - tell us.

So you agree that with blown air systems the surface temperature of interior surfaces will always be equal to or below air temperature?

Mean radiant temperature is simply the area weighted mean temperature of all the objects surrounding the body. It will be positive when surrounding objects are warmer than the average skin temperature and negative when they are colder. It follows that hot air systems, which cannot produce surface temperatures higher than the air temperature will therefore require higher, not lower, temperatures than radiant systems to achieve similar levels of comfort. Radiant heat has a high MRT. Hot air has a lower MRT, it is inescapable.

It is simply basic physics and physiology, nothing magic or complicated about it.

no - which is why fancy controls are not usually needed.

If he doesn't understand the physics of heat loss and gain how then does he design it?

Is it?

Of course - because developers want the cheapest quickest and simplest systems they can stuff in their little boxes. Quality is not an issue.

Most of my houses were not army houses.

and never lived with the consequences of any, like most plumbers.

If you care to let us know your qualifications and experience I'll compare them for you. I'm interested to know you consider yourself to be better experienced and qualified in these matters than the manufacturers senior designer is.

It was, he doesn't.

[SC]

Ah the best test of all, the cat test. Just looking at an old video of a holiday in S Ireland on a farm with stables. A flowerpot with soil sitting on a sunny window had seven kittens piled into it. Every so often one would struggle from the bottom of the heap and pile back on top. V cute.

[Peter Parry]

It can make them very paranoid. Everywhere they sit gets nice and warm. Cats as you know have to be in the warmest place so this confuses them greatly - what if somewhere else is warmer? They won't know until they sit on it so this entails setting up an extensive research programme of sitting everywhere in turn.

They usually then settle for the one place you always trip over them of course.

[The Natural Philosopher]

You lack the attitude or aptitude to get in .

[The Natural Philosopher]

Hmm. Once again a total failure to actually grasp the point being made.

[The Natural Philosopher]

I think, unlike IMM, you have grasped the essentials.

Go for it.

[The Natural Philosopher]

Humidity.

37C and say better than 30% humidity is as uncomfortable as 50C and

[The Natural Philosopher]

Precisely.