HVAC "n" stuff!

[FROSTYFRECKLE]

I am looking for a favour from any clever Grape who understands HVAC calcs - bottle of fine Malt for anyone who can

Question 1 - what are the calculations used to calculate the Thermal Gradient of a room. Radiator has been placed behind a door (don't know the bright spark who thought that would be a good idea), so heats up only half the room. The "Cold Zone" is in front of the window, radiator is at the other end of the room (I know the Cold Zone need not be at the window but in this case it is). Nearly everything is mouldy due to condensation at the cold end of the room.

Question 2 - room is approx 3m x 4m. Exposed radiator pipes run along one and a half walls. One 4m length wall is uninsulated. Radiator is in front of the window. Again room is seriously badly affected by condensation and mould. What do you suspect the culprit to be? And how would I "show" the culprit?

I am trying to do these calculations to help a friend. Their home is ruined by damp. They use a dehumidifier, air the house etc, etc but to no avail. Problem with damp only started after their landlord (housing association) put in a new heating system, prior to this no problems. Landlord are acting like a bunch of t*ssers. My friend is disabled and can't argue their corner. When you walk into their house you can see so many problems with the heating - I could have put it in better. I need to physically show their HA calcs nobody can argue with. Anyone? HELP

PS Have already Googled and found some useful sites but need to make sure I don't do anything wrong.

[pigletwillie]

Right, condensation is made by warm air meeting a cold surface, Ie a tiolet cistern which is full of cold water in a warmish house very often will have beads of condensation on it.

The room needs ventilating but also some investigation to where all of the mioisture is coming from, a tumble dryer perhaps,a fridge or freezer, even the breath of a sleeping person.

If the heating system is via a boiler and rads, then HVAC calcs will be of no use, several web sites will give you the sizes of radiator (measured in BTU,s) to heat that room but as they do not move air about as mentioned HVAC calcs will be of no use.

Without seeing the problem its difficult to "see" a solution I am afraid.

[SueA]

It does sound strange if they are putting the heating on regularly & airing the rooms but one problem which I'd think the landlord should sort out is the uninsulated wall as this can lead to condensation, maybe they should have the damp proof course checked out as well as it may not be working properly. If they won't do anything major to the heating perhaps they could put in an additional electric heater at the 'cold' end of the room.

[FROSTYFRECKLE]

Oops I thought Thermal Gradients etc were part of HVAC I've found a website that gives me calculations for the Thermal Gradient of a room (which I think is the problem in their living room) so maybe I should work my way through it But as I have your attention PW and I'm guessing (and hoping) you know about central heating etc here's a question for you - my friend's heating was Storage Heaters until Dec 2008 when it was changed over to an electrical central heating (looks like normal radiators but heated by hot water from a hot water tank - electrically heated). Have you ever heard of condensation/damp being caused by this type of heating? No damp present with Storage Heaters.

No tumble driers, doesn't dry clothes in their home etc, one person lives there (but has carers in), using a dehumidifier. Sue forgot to mention they have a Delonghi oil filled radiator at the cold end of their living room but it is still baltic.

[Hilary B]

Condensation occurs when there is not a 'good balance of heating and ventilation', which basically means that the warmer the room, the more ventilation you need to prevent condensation occurring. If the heating is adequte, but too uneven, simply adding a fan to move the warm air to the colder areas might help a lot!
An electrically powered radiator system shouldn't cause any more condensation than any other system, unless the 'tank' is getting TOO hot and steam is being produced at some pressure-escape point (depends whether it is a pressurised system, with pressure control, or an unpressurised system with a header tank, I think electric ones are mostly the former).
Steam from hot bath/shower, or even cooking (including boiling the kettle for tea) all put moisture in the air, and when that moisture hits something cold, condensation follows. Are there extractor fans in kitchen and bathroom? The purpose is to remove warm damp air (NOT to remove bathroom smells as so many folk seem to think) so if they are there USE them!
Has the loft been insulated? If so, can fresh air still get into the space above the insulation? (there should be a gap between any insulation and the underside of the sarking, which is that fabricky stuff under the tiles/slates) If the insulation is laid flat over the ceilings, is there a gap at the eves to let air in and out?
I don't know the calculations, but I do know a bit about condensation and houses, being married to a Chartered Surveyor!