Heating an empty small house in winter

DoneWorking

A friend has asked me to look after their empty house over the winter

They are concerned about freezing pipes and flooding 

What's best option for a combi boiler 

Set timer to come on for 12 hours total per day spread over morning evening and in-between 
Set flow temp to radiators at 50 or 60 degrees C 
Set radiator TRVs at 3 

Or 
Set timer to run 24/7
With the above settings

There are no room thermostats 

Or are there any other options I haven't thought of 

Please let me know your thoughts

Obviously he wants to keep cost reasonable as no one is living in the property 

I can visit it once a week 

kinger101

My advice would be they set it how they want it and you check periodically everything.

You shouldn't be having to work this out for them.

Heedtheadvice

... but to answer the question......

Three approaches.

Drain all systems and set the boiler go it's frost free setting, ( safe to prevent freezing at combi boiler, all other systems dry/ drained but  risk that some water  containing locations are missed such as cold mains feeds, outside taps etc.....and the property might become damp. Very low running  cost.) Boiler on permanently but everything else is off. Bit of  faff to do or needs a plumber to ensure fully drained.

Set the boiler to a low setting 50 max( as not much heat will be needed), set all radiator trvs to their frost free setting, run all the time or overnight with a top up late afternoon. Run all the time if a very cold spell. Easy to do, low running cost. The peripheral locations ( like outside tap feeds could freeze if in colder  such as underfloor locations.

 or

 boiler as above temperature and  trvs at a number equivalent to 13deg C. Run  continuously. A lot cheaper than normal heating costs, prevents freezing except in the very worst weather and importantly( if not unfurnished ) keeps the property dry too.

A big however  - the owners should advise you as there most likely will be insurance  Ts &Cs that have to be complied with!!

twopenny

Agree with Kinger.
Why are you having to take this responsibility? 
You are kind enough to do this for them they should at least have to set it up and you just check.

If they have properly lagged the pipes and tank in the loft there shouldn't be much problem.
You could run the water through the taps each visit. 
If it's absolutely freezing for a period leaving the heating on very low should help. But if setting remember it gets coldest overnight and early morning so set it for then. 

DoneWorking

kinger101 said:

My advice would be they set it how they want it and you check periodically everything.

You shouldn't be having to work this out for them.

I'm doing it for them as they are not around and don't have the time to sort it out.
I've said I would help them and have spoken to several heating engineers I know

Their advice has been different options.
Hence my post on here for guidance on the best option from people with knowledge and experience of this issue .

subjecttocontract

Hopefully you doing it for them because they don't have time won't give YOU a problem if it goes wrong. It's really their responsibility and in your shoes I'd want to ensure there would be no come backs if it results in a frozen pipe or leaks or worse.

WIAWSNB

Hi Kinger.
Good advice above to have the decision confirmed by the owner, in writing (say email).
How long will it be empty for? Again, as above, ask them to check their insurance requirements.
Finally, where are you located? And how close are you to the property?
For 99.9% of properties, it'll be more than adequate to keep the boiler timed to be on 24/7, with TRVs set to '1'. Even this is technically 'overkill' - 'frost' setting would do, but I think a minimum background 'warmth' from a '1' will cost very little, and be welcomed by the house.
To be clear, I would barely expect the CH to run at all at this setting, since the outside temp is unlikely to be low enough, and the house will benefit from solar gain. So, in a 'normal' British winter, the energy cost at '1' is going to be 80% (figure plucked from air) 'standing charge', so unavoidable in any case. Actual gas use on top is unlikely to be more than, what, £5-odd pm?!
Then, since you are closeish to the house, keep an eye on the forecast, and consider upping the TRVs to '2' should a few days of zero temp be promised.
As part of the checking routine, look for condensation forming on the insides of window panes, or any mould forming. (What age and type of house?) Any signs of either should be addressed, usually by simply ventilating the affected rooms - Ie, crack their windows open to locked vent setting, and close their doors to the rest of the house. Keep monitoring that it's sorted.
Finally, take photos of boiler turned on, and a few TRV settings. Leave a wee notebook in the hallway, and sign it every time you visit - take a photo each time too. Write down any observations.

Lorian

Are they sure the house properly insured if no one is. Living there? The insurance company will have requirements.

Eldi_Dos

DoneWorking said:

A friend has asked me to look after their empty house over the winter

They are concerned about freezing pipes and flooding 

What's best option for a combi boiler 


There are no room thermostats 

Or are there any other options I haven't thought of 

Please let me know your thoughts

Obviously he wants to keep cost reasonable as no one is living in the property 

I can visit it once a week 

The best thing to do for safety and costs is to upgrade their heating controls to give better protection and reduce costs, if they are tech savvy they may even be able to monitor from afar.

Failing that I would set boiler to around 50 deg flow temperature and TRV's to 1 on the scale.
Before going on your weekly visit check with the Met Office forecast and decide then the timings required, erring on the side of caution.

Turn water off at stopcock and open and drain all cold taps, leaving taps open.Check with a heating engineer what is best policy with hot taps, mentioning it is a combi boiler.

I would also plunge out traps and U bends and fill with RV ( Recreational Vehicle ) Antifreeze, you will get this in Caravan and Motorhome supply shops, and it is deemed safe for the enviroment. It may seem like a bit of overkill but if property is to be left unattended during a prolonged cold spell I think it is a good idea, as traps that are unused during frigid temperatures with winds going through the drains can dry out.

Get two or three small USB fans and position and move them about the property during your weekly visit, this will help stop any mould that may form in area's of stagnant air.

I would also get some timers and have table lamps going off and on in various rooms so the house looks occupied.

If I was feeling a bit avarice I might be tempted to do a bit of house sitting with the heating turned well up during a cold spell.

subjecttocontract

That sounds like it's becoming a part time job rather than a ' pop in once a week to check'.

Albermarle

For 99.9% of properties, it'll be more than adequate to keep the boiler timed to be on 24/7, with TRVs set to '1'. Even this is technically 'overkill' - 'frost' setting would do, but I think a minimum background 'warmth' from a '1' will cost very little, and be welcomed by the house.
To be clear, I would barely expect the CH to run at all at this setting, 

Normally at least one radiator on a system should not have a TRV, and be fully on all the time.
If the boiler is on 24/7, then it will run 24/7 ( albeit modulated down) and this one radiator will be hot all the time. 
Personally I would just have the boiler timed to come on for half an hour in the evening and early morning, and probably set the TRVs at around 1.5. Just an opinion though.