Cavity Wall Insulation... *Updated*

[JohnD]

it wont magically become warmer just because there is insulation in the walls.

I have never claimed that insulation magically generates heat.

However, an insulated room which is, or has been, heated, will be, and will stay, warmer than an uninsulated room which has received the same amount of heat energy.

as I said, I am ignoring the possibility that he will be insulating a shed with no heating.

As for your metaphor of a thermos flask of iced coffee, the insulation will reduce the amount of heat reaching the coffee, so it will retain its temperature longer than if you carried it in an uninsulated milk bottle. Heat travels from a hotter to a cooler body, and insulation reduces transfer of heat.

 

[^woody^]

The OP complains that his bungalow is not "warmer" since having it insulated

It wont ever be "warmer" unless he turns the heating up to a higher setting than he did previously.

All the insulation will do is allow the OP to turn the heating off once he has heated it to the temperature he did previously, and the bungalow will stay at that temperature for a longer period of time before the heat escapes and he needs to turn the heating back on again to bring the temperature back up.

Non of this is making the bungalow any "warmer", only reducing the amount of gas he needs to burn to keep the house warm ..... ie at the same temperature he was heating it to before it was insulated

So its not a combination of reduced energy use and a warmer bungalow, it's just reduced energy use in keeping the bungalow as warm as it was before being insulated

 

[JohnD]

When I had CWI installed:

The walls were warmer so there were not cold patches away from the radiators

If I came home at lunchtime the house had not cooled down so much, so it was still warm even though it had not been heated for five hours. If I got up early in the morning it was not cold even if the heating had been off all night.

On a sunny cold day, solar gain exceeded heat loss so even with the heating off it was warmer than before I had CWI

The rooms with small radiators came up to temp instead of being underheated

All that, and less gas used as well.

And yet you claim my house was not warmer as a result of CWI.

 

[AronSearle]

I see what woody is saying, but it is ass backwards pedantantry.

Back in the real world more insulation will increase average wall surface temperatures.

The OP's issue is likely crappy dense block walls where 50mm does not really cut it.

 

[Christian and Beccy]

Just checking back in on this one. It's been about a month since I went around and opened all my trickle vents.

Obviously in that time, the weather has got colder, but the condensation is at an almost unbearable level. It is even collecting on the Downlighters in the ceiling (there is of course a gap in the insulation where these are fitted, something else I need to look at). They are JCC FG LED Downlights and I can't imagine the moisture will do these any good at all.

I run the De-humidifier during the day to try to benefit from the energy generated by our PV rig, but we're getting towards the point where we will need to run the De-humidifier either overnight instead or 24/7 and just suck up the high running cost.

I'm beginning to wonder if we have a problem with the CWI as I don't recall the problems being this bad before we had it installed, although that was about 8 years ago now. Would it be worth getting someone round to discuss our CWI and whether it's been done correctly?

The Windows were fitted 10 years ago, uPVC Double Glazed. The condensation is worse on these Windows than the ones in the extension (fitted 4 years ago) and the large Patio Door (fitted last year, we spec'd the best and most energy efficient glass we could buy for that). Might the original units be knackered and need repair/replacement?

Regarding the warmer room debate, of course my heating runs on a timed/thermostatic schedule, I'd expect the house to feel warmer with better insulation due to retaining the heat better, although I see validity in the point about the insulation itself not generating heat.

Roughly speaking, I have the heating set to a base temperature of 17° as a bottom limit and it raises to 21° at around 18:00 for the evening, returning to the base temperature at 22:00. I comes on in the morning just to lift the temperature to 18°, which we find more comfortable. However, I have just raised the overnight temperature to 18° to see what effect this has.

I also don't use the Auto-Schedule/Auto Away on the Nest as I don't think it performs well enough on a Radiator-based Central Heating System. For me, the biggest benefit of the Nest is being able to control the heating from away and that's how I use it, so it's not as though the heating schedule is messed up due to our movements. The Nest reports a humidity inside the property of 72% currently (at 09:30 this morning).

 

[JohnD]

Despite the title of the thread, it seems to me that your presenting problem is condensation and excessive humidity. So let's think about potential causes.

Do you drape wet washing around the house?
Is the bathroom extractor powerful, and when do you use it?
same for the cooker hood
Have you got a water meter (helps identify leaks)
Have you looked in the loft for damp and roof leaks
A photo of the wet patch in the bathroom might be informative. Bathrooms are well supplied with steam, pipes and water.

 

[Christian and Beccy]

JohnD, thanks for your help.

We do dry washing in the house, although there is only 2 of us at home, so try to keep it minimal and ensure that the Dehumidifier is definitely on 'high' at this time.

The bathroom extractor is used every time the shower is used, I admit we don't keep the bathroom door closed, but I plan to change that. The extractor stays on until the steam has cleared, then I switch it off manually. I try to make sure the heating is on when we shower/bath, of course this helps with clearing the moisture. I find the bedroom condensates more when the en-suite shower is used, so I try to avoid that during the Winter. I have a fairly big Velux in there, so have to choice of either the extractor or opening the Velux, which is great in the summer, although I think opening the Velux compounds the problem when it's cold outside so tend to use the extractor.

The Cooker Hood is used almost every time the hob is used. We don't really get any damp in the Kitchen, despite it having a 4.2 metre Patio Door. There is a strip of condensation covering about 6-8" of the bottom of the glass panels in the morning, but nothing compared to the rest of the bungalow. That and the Living Room are the least troublesome rooms. The bay window in our bedroom is about 2.5m wide and I can easily fill the tank of my Karcher Window Vac clearing that window alone, in fact this morning I had to empty it and go back for a 2nd go.

Yes, we have a Water Meter, I'll do some investigating there.

No obvious leaks in the loft and no signs of any problems.

I've cleared most of the mould from the Bathroom in the last couple of weeks. It's tiled from floor to ceiling so it manifests itself in mould in the tile grout and some patches where the tiles meet the ceiling. It's North facing, so I guess understandable that it'd be the worst.

 

[JohnD]

try the experiment of putting both bathroom extractors on, and leaving them on for 24 hours. I will be surprised if your condensation problem does not improve.

If the fans are worn out and noisy, they can easily be changed for better ones with ball-bearing motors. Running cost is negligible. Ones with built-in delay timers mean you haven't got to remember to turn them off. Some cheap "builders fans" are weak and ineffective, so a photo would be useful.

A wet bathtowel or mat continues throwing off water vapour long after the steam has cleared.

Wet washing is a terrible source of damp, and the water vapour will diffuse through your home unless it is in a room with an effective extractor and the door shut.

The water meter has a bubble in the middle of the window, this rotates all the time water is passing through. It should be motionless when all taps are off and cisterns are full. You will need a torch.

 

[Nige F]

Check you air bricks carefully. On my Daughters blown fibre installation, they knocked in plastic pegs in all the holes nearest the edge of the brick. This stops the fibre from filling the whole air brick area and allows 2/3 of the ventilation there was before.
Frank

That'll be 2/3 of sweet FA in a teracotta brick then Change them for plastic ones