Empty House - To Heat or Not To Heat?

John_Pierpoint

DGJsaver wrote: »

yep , big thick victorian solid walls

Bad luck

http://www.diydata.com/information/u_values/u_values.php

DGJsaver

John_Pierpoint wrote: »

Bad luck

http://www.diydata.com/information/u_values/u_values.php

Are you annoyed because youre advice was wrong ?

DGJsaver

DGJsaver wrote: »

but either way the OP should play it safe anyway and use the heating

Dan

This is the answer to the question regardless of what johnny boy thinks about my walls and how unlucky i am:eek:

Biggles

A 10 or 12 degree setting - water off, heating 24/7 - will do the job.

The heating will only cut in when needed and that may not be very often, depending on how mild the weather is.

x_Wilco_x

Biggles wrote: »

A 10 or 12 degree setting - water off, heating 24/7 - will do the job.

The heating will only cut in when needed and that may not be very often, depending on how mild the weather is.

So, leave it on 24/7 on a low setting rather than using the timer as they normally do? I am pretty sure it is usually only on evenings and weekends via the timer but obviously set higher...

Biggles

Somewhere from 10 to 12 deg will protect against frost. But if the heating were set to switch off at night, it could drop well below that during a cold spell.

John_Pierpoint

I am a little bit worried that some people on this thread do not understand U values or why pipes burst and the difference between thermal resistance and thermal mass.
This link displays a thick Victorian wall made of heavy bricks.
http://www.builddesk.co.uk/sw56126.asp
This wall has bad thermal resistance and it is difficult to improve it, as dry lining the inside reduces the building's thermal mass and removes the period features such as picture rails and plaster coving. Putting insulation on the outside destroys the appearance of the property. If the property is detached the problem is particularly acute. The heavy bricks store a lot of heat, this could be a good feature if the building was insulated on the outside; then the thermal mass means a steady temperature 24/7.
Cool in summer and warm in winter. However it also means 24 hours needed to reheat the house when it has got cold.
The main risk of leaving a modern house empty in the winter is burst pipes. Depending on the relative positions of the thermostat and the coldest point in the plumbing, there is a risk that a pipe could freeze on a cold night, when the thermostat still thought the house was relatively warm. So it is advisable to keep the water moving in the system and have all the radiators turned on. In this case it may be possible to set the boiler switch on/off temperature really low.
Each installation is different, the more up market designs measure the outside temperature and have a "frost stat" setting to turn on the boiler when the outside temperature approaches zero.

When pipes "burst" it is not the ice but the water that is being compressed by the growing plug of ice that usually forces open a joint, so the burst does not have to happen at the coldest part of the system. I have a stand pipe in the yard. It freezes every winter but as the ice grows from the tap backwards it simply pushes the water backwards into the main.

x_Wilco_x

John_Pierpoint wrote: »

I am a little bit worried that some people on this thread do not understand U values or why pipes burst and the difference between thermal resistance and thermal mass.

I haven't got a clue what you are talking about but if you could advise on the optimal settings for the senario in my original post then that would be great...

The house is a 1930's solid brick built semi. Double glazed with well insulated loft etc...

What would be best set up for timer and thermostat when the house is left empty?

Thank you... Oh - please keep it simple!!! :T

John_Pierpoint

May or may not be a cavity wall; may or may not be ALL the same sort of wall. The 1930's were the period when the cavity concept was adopted by most of the speculative builders, mainly to save construction costs, speed construction and allow less skilled techniques to build the inner half of the wall.
To be safe, I would go for the advice in posting #2.
It won't be the cheapest solution and I don't know the minimum setting on the boiler thermostat. I also have no knowledge of the routing of the pipes and the draught proofing of the building.
Constantly circulating on "almost cold" covers you for pipes that have been left uninsulated and poked into uninsulated bits of loft and utility room. With a bit of luck the ordinary domestic water supply runs alongside and ABOVE the central heating pipework. If a well trained plumber was used for both.

The days are getting longer and the worst of the winter should be over. In my limited experience it is the extended Christmas holiday that is the greatest risk. (EG teacher gone skiing for 10 days).

Leightonian

That loooks like the advice already given by everyone already ?
seems that you are scarmongering a little