Why is my house so cold?!

[Cognis0]

3 hours ago, billt said:

No one seems to have pointed out the obvious: the house isn't being heated enough, or at all. Get the boiler fixed. 13C is about right for an unheated house at the moment.

 

If we go away for a few days with the heating set to frost protect the house is cold (if I've forgotten to turn it back on remotely a few hours before we arrive). Heating on for a few hours and it's back to normal.

 

All the stuff about insulation etc is fine, but it won't make the house any warmer.

When I was young my mum had to light the coal fire to start to warm up the Victorian house in the mornings. A few years later we had the luxury of off-peak storage radiators. I was 21 before I experienced central heating. But I have never lived in a house which is intrinsically "cold" as this one is. There is something in the make-up of the construction that seems to make it cold. I have no doubt that the major renovation works which we are planning will have the desired result ~ in the meanwhile we will probably be burning lots of gas when the new boiler goes in next week....

[TonyT]

Maybe it’s worth investing in a one or a couple of oil filled heaters. Handy to keep on and not a fire risk with dust etc during renovation.

 

2.4kW version available from screw fix  for about £50.

 

 

[SteamyTea]

14 minutes ago, TonyT said:

2.4kW version available from screw fix  for about £50.

Get 2 kW fan heaters for a tenner, and they warm all the air up in a room, not just the bit by the ceiling.

Cheaper than a new boiler and a winters worth of gas.

 

Did we establish of there was a fireplace/chimney?

[Cognis0]

45 minutes ago, SteamyTea said:

Wash your mouth out with soap and vinegar.

 

Why would a floor suck the heat out any different from a cold wall?

 

There are those that think that mass equals free heating, and then there are those that study this and know it cools a house in the UK climate. Except in a heat wave, then it gets warmer for a day or two, but nowhere near external peak temperatures.

 

Seems like you need to insulate and get the air changes under control.

I have been sceptical about this thermal mass thing. But the fact is that the 4000ft2 detached Georgian house I lived in for 18 years until 12 months ago was far, far warmer than this 1960s bungalow. It had dozens of large, drafty single glazed windows. The only thing that might have been in its favour was the 450mm thick solid stone walls, ie, thermal mass. But perhaps I am wrong and will now head for the bathroom...

[Cognis0]

19 minutes ago, TonyT said:

Maybe it’s worth investing in a one or a couple of oil filled heaters. Handy to keep on and not a fire risk with dust etc during renovation.

 

2.4kW version available from screw fix  for about £50.

 

 

Sounds like a plan!

[TonyT]

I know but, oil filled are a bit safer in a dusty, remodelling environment.

I keep one on all the time ticking over on low in our joinery workshop to  help keep rust off the machines/ prevent glues and adhesives getting cold etc so 

[Cognis0]

4 minutes ago, SteamyTea said:

Get 2 kW fan heaters for a tenner, and they warm all the air up in a room, not just the bit by the ceiling.

Cheaper than a new boiler and a winters worth of gas.

 

Did we establish of there was a fireplace/chimney?

Yes, the bungalow has a classic 1960s fireplace, which we used to great effect last night burning some logs. When I say great effect I of course mean that it looked good, but produced little heat!

[ProDave]

The coldest house I can remember is the typical 1930's 9" solid wall semi.  I spent my childhood years in one and recall even with a piping hot radiator in each room, shivering in my bedroom.  Then for some inexplicable reason I bought one myself as my second house.  That came with storage heaters that were simply incapable of keeping it anything approaching warm in the winter.  We extended that one so at least the side extension was not as badly insulated but it still cost a fortune to heat.  And being solid walls no simple way to insulate those.

[ProDave]

Re plug in heater.  NEVER leave a fan heater running unattended.  If the fan seizes and the over heat trip fails to trip, the plastic just melts as the element overheats without the airflow.  Far safer are the cheap metal cased convector heaters with thermostats and variable power settings available in a variety of names for about £20 each.  We have 3 that were used in the static caravan and one is still in use as an excess PV dump load.

[ToughButterCup]

2 minutes ago, ProDave said:

...  We have 3 that were used in the static caravan and one is still in use as an excess PV dump load.

 

First .... excess PV in Bonnie Schottenland? Honest??

 

Next howdya manage to divert the output to a convector  heater then? 

[SteamyTea]

22 minutes ago, Cognis0 said:

But the fact is that the 4000ft2 detached Georgian house

Probably had a better volume to surface area ratio.

Easy enough to work out.

8 minutes ago, ProDave said:

NEVER leave a fan heater running unattended.  If the fan seizes and the over heat trip fails to trip, the plastic just melts as the element overheats without the airflow. 

True, eventhough I sometimes forget to turn nine off.

I do have a cheap metal one.

Thing about convection heaters is the convection. We don't put radiators on ceilings, but that is where the air from an electrical rises to very quickly. If the element was not so hot, the air may have a chance to cool before it rises up.

[ProDave]

2 minutes ago, ToughButterCup said:

 

First .... excess PV in Bonnie Schottenland? Honest??

 

Next howdya manage to divert the output to a convector  heater then? 

My PV will generate up to 3.6kW

My immersion heater on full consumes 2.8kW

If the PV is running full chat on a sunny day, and nothing else in the house happens to be on, 800W could get "wasted" to the grid.

 

I have one of these convector heaters set on it's 700W setting, and connected to a wireless controlled switched socket.  If my home made (Arduino) PV diverter gets close to 90% immersion heater power, it turns on the radio controlled relay to send an additional 700W to the dump heater.

 

It is of most use in the spring when we can have some sunny weather and it is still cool enough for a little extra heat in the house to be useful.  In the summer it gets unplugged and we just have to let some go to waste.

[SteamyTea]

3 minutes ago, ProDave said:

let some go to waste

Hardly waste. It helps lower the grid costs and CO2.

[ProDave]

4 minutes ago, SteamyTea said:

Hardly waste. It helps lower the grid costs and CO2.

Okay not "waste"  just "not to my maximum benefit"

 

Cue the argument about punitive export payments and only for those that pay extra for an MCS install which will never be repaid by said punitive export payments.  It hardly encourages one to do anything other than self use it.  I considered putting the dump heater out in the garage for the summer so I could still self use it all.

[TonyT]

19 minutes ago, ProDave said:

My PV will generate up to 3.6kW

My immersion heater on full consumes 2.8kW

If the PV is running full chat on a sunny day, and nothing else in the house happens to be on, 800W could get "wasted" to the grid.

 

I have one of these convector heaters set on it's 700W setting, and connected to a wireless controlled switched socket.  If my home made (Arduino) PV diverter gets close to 90% immersion heater power, it turns on the radio controlled relay to send an additional 700W to the dump heater.

 

It is of most use in the spring when we can have some sunny weather and it is still cool enough for a little extra heat in the house to be useful.  In the summer it gets unplugged and we just have to let some go to waste.

Hi Dave ,

 

Have you done a thread on the diverter, interested in your home made version?

[ProDave]

3 minutes ago, TonyT said:

Hi Dave ,

 

Have you done a thread on the diverter, interested in your home made version?

Here

 

 

[Cognis0]

57 minutes ago, ProDave said:

The coldest house I can remember is the typical 1930's 9" solid wall semi.  I spent my childhood years in one and recall even with a piping hot radiator in each room, shivering in my bedroom.  Then for some inexplicable reason I bought one myself as my second house.  That came with storage heaters that were simply incapable of keeping it anything approaching warm in the winter.  We extended that one so at least the side extension was not as badly insulated but it still cost a fortune to heat.  And being solid walls no simple way to insulate those.

My first house was a 1936 2 bed end terrace. Cost £10k! Pretty basic house, but I don't remember it being that cold...

[Iceverge]

3 hours ago, Cognis0 said:

installing trickle vents

Groan, I should have though you had quite enough holes in the house as is. 

 

"Thermal Mass" is promoted by the concrete industry. Can't think why ?

 

https://www.irishconcrete.ie/concretes-multiple-benefits/thermal-mass/

[Gone West]

On 24/10/2021 at 17:09, Cognis0 said:

I welcome your comments..

I would wait until you have a replacement gas boiler fitted and check that all the radiators are working correctly before deciding your house is especially cold. We moved into a bungalow in May that had been empty for a year. It was cold, as it hadn't been heated and the construction is a mix of 650mm thick stone walls, concrete block walls and insulated concrete block walls. We filled the oil tank and turned the central heating on and after a couple of weeks the structure was warming up (thermal mass?) and now it's a nice 23C throughout the house.

[SteamyTea]

4 minutes ago, Gone West said:

after a couple of weeks the structure was warming up (thermal mass

How much was just water/moisture evaporating, it takes 4.2 kJ.kg^-1.K^-1 to heat water.

But

2470 kJ.kg^-1.K^-1 to change liquid water to vapour (@13°C).

 

Brick, stone, earth take ~0.8 kJ.kg^-1.K^-1

 

I think people often forget this point.

[Gone West]

4 minutes ago, SteamyTea said:

How much was just water/moisture evaporating, it takes 4.2 kJ.kg^-1.K^-1 to heat water.

But

2470 kJ.kg^-1.K^-1 to change liquid water to vapour (@13°C).

 

Brick, stone, earth take ~0.8 kJ.kg^-1.K^-1

 

I think people often forget this point.

So if there is around 100m2 of walling, 500mm thick, internal surface at 13C and the internal air is heated by 10C to 23C how much of the energy going into the house is evaporating moisture and how much energy is needed to bring the internal wall surface temperature to 20C.

[SteamyTea]

47 minutes ago, Gone West said:

So if there is around 100m2 of walling, 500mm thick, internal surface at 13C and the internal air is heated by 10C to 23C how much of the energy going into the house is evaporating moisture and how much energy is needed to bring the internal wall surface temperature to 20C.

Tricky that one without measurements.

Have to work out the mass of water 'in the wall'.

Then the genuine wall temperature, which will be somewhere around the median hourly temperature.

Then the amount of water that gets reabsorbed by the wall when it is close to the vaporisation temperature.

 

According to this (first search hit https://theconstructor.org/practical-guide/water-absorption-test-on-bricks/2796/), around 15% of a brick dry mass can be added.

So a brick that has a mass of 2 kg may have an extra 0.3 kg of water in it.

 

To evaporate half that water, 0.15 kg, will take 411 kJ (I made a mistake above, it should be 2740 kJ.Kg^-1 as the temperature does not change).

The remaining water will take 4.41 kJ to get from 13°C to 20°C

The brick from 13°C to 20°C will take an extra 11.2 kJ

 

So that is a total of 426 kJ

As percentages:

Vaporisation 96%

Retained Water 1%

Brick 2.6%

 

This is not strictly correct as not all water, or the half I used as an example, in the brick will magically vanish at 13°C.

But you get the idea, the actual brick takes very little energy.

 

The people that study thermal properties of building materials know this.

 

Edited October 26, 2021 by SteamyTea

[Gone West]

10 minutes ago, SteamyTea said:

So a brick that has a mass of 2 kg may have an extra 0.3 kg of water in it.

 

10 minutes ago, SteamyTea said:

To evaporate half that water, 0.15 kg, will take 411 kJ

 

11 minutes ago, SteamyTea said:

The brick from 13°C to 20°C will take an extra 11.2 kJ

Since moving in the internal RH has roughly gone down from 65% to 55%. The internal wall surfaces are, as far as I can tell, gypsum plaster on sandstone or concrete block. From the brick example it seems as though there is potentially a lot of water stored in the material which I think would probably be less in hard plaster and sandstone, but I get the gist of what you are saying. I guess the temperature gradient within the solid stone wall would go in the opposite direction to the moisture gradient, as the house warms up.

[Ferdinand]

13 hours ago, Cognis0 said:

My first house was a 1936 2 bed end terrace. Cost £10k! Pretty basic house, but I don't remember it being that cold...

 

How much older are you now, and does that alter perception?

[Ferdinand]

16 hours ago, Cognis0 said:

Good comments, thanks. The house seems to be bone dry with no evidence anywhere of any water ingress. There are no perceptible drafts, although when the Thermabead was installed they insisted on installing trickle vents in the windows. We have just come back from a week away, and whilst we left the trickle vents open the bed linen does seem to be damp ~ so this needs further investigation.

 

Evil, 1970s technology. Fill with foam.

 

One way to deal with those is MVHR.

 

My poor man's MVHR is a PIV loft fan, and a HR trickle fan (eg Vent-Axia Lo Carbon Tempra) at the far end of the downstairs.