Central heating in a garden outhouse...

junksamiad · Jul 24, 2020

Hi there,

I am building a single storey outhouse at the bottom of my garden and I want to install two radiators in there. I’m just trying to ascertain whether it will be feasible to just connect them to my existing central heating circuit in the main house?

My current boiler is a Vaillant ecoTec plus 832. The outhouse will be approx 20 metres from the main house. I would like the rads in the outhouse to be K2’s @ 1800 x 600 and 400 x 600. In the main house I currently have 12 rads. The house is a 4 bed semi with a utility room and GF and FF bathrooms.

So my main issue is whether running the central heating pipes 20 metres to the extra 2 rads in the outhouse building will be too much of a stretch for my existing boiler to handle?

Any advice is very much appreciated so I can work out the best solution.

Thanks again.

PETE 123 · Jul 25, 2020

In winter pipes may freeze.

junksamiad · Jul 25, 2020

PETE 123 said:
In winter pipes may freeze.

Cheers Pete. Yes, I had considered that. I planned to put lagging round them, then also possibly run the pipes through a rain water pipe with rock wool inside the pipe aswell.
The reason I’m seeking other opinions is because I’ve had a couple of hearing engineers look at the scenario. One has said the boiler will cope fine. Another has said it may struggle. I don’t know who’s advice to trust. I’m a builder myself so I’m just trying to find the best solution.
Thanks again.

SimonG · Jul 25, 2020

Separate circuit, two port valve, timed, thermostat, frost stat and pipe stat.

oz-plumber · Jul 25, 2020

As above and make an allowance to install a second pump to service the out house.
Wire it in with the thermostat or the zone valve for the outhouse.

Slightly left field, but it may be necessary to get heat out there.

gpbeck · Jul 25, 2020

Insulate it very well then just use electric heating. You will pay the bills for many years from savings on installation and maintenance.

Last Plumber · Jul 25, 2020

You would need to bury the pipes 2'6" below ground to avoid Frost.

If that's the plan, I personally would do as both @SimonG and @oz-plumber suggested but also incorporate a low loss header or plate heat exchanger to prevent the extra pump from effecting the existing system. Someone experienced needs to see it really.

If those are the only 2 rads you are using, it sounds like it is around 3 Kw?

Is it not easier to use electric heaters or a Drugasar gas wall heater (other makes are available). You could possibly run one of those on propane if you didn't want to run gas down there.
The Dru heaters have a built in stat and don't require wiring unless you plan to use an electric time switch (true for last time I installed them).

Murdoch · Jul 25, 2020

What is the outhouse going to be made of? how well will it be insulated? and what is it going to be used for?

junksamiad · Jul 25, 2020

Murdoch said:
What is the outhouse going to be made of? how well will it be insulated? and what is it going to be used for?

Thanks for all the replies so far.
It will be office space. It will be double skin block and render, 300mm insulated cavity wall. I normally just insulate the cavity with cavity slab full fill.

Murdoch · Jul 25, 2020

junksamiad said:
Thanks for all the replies so far.
It will be office space. It will be double skin block and render, 300mm insulated cavity wall. I normally just insulate the cavity with cavity slab full fill.

I would suggest getting a spark to sort out the supply, electrics and advise on the electric heating

gpbeck · Jul 25, 2020

Does your heat loss calculation suggest 3kw? Must be massive!

SJB060685 · Jul 25, 2020

Do a heat loss calculation first to find out what watts or kilowatts is needed for the new building.

gmartine · Jul 26, 2020

Nows the time to increase the amount of insulation you were going to use (say add 100 +mm insulation board internally inc roof) so your left with less than 1.5 kw or less to heat building which you can easily manage with a couple of slim oil filled panel rads. The outbuilding will be more comfortable in the summer too without any need for any especially large electrical provision.

king of pipes · Dec 11, 2020

Insulate the hell out of the place floor walls ceiling with 100mm of celotex at construction stage , then use electric timed panel heaters , are you having a toilet and small basin a kitchen sink with the need for hotwater ?? You must consult a electrician before doing anything, personally I wouldn't connect it to the house gas boiler the pipe run and install costs just wouldn't be make it viable

Brambles · Dec 11, 2020

I think you will find that Building Regulations, require the pipes to be within a preinsulated pipe with an outer wrapping. The pipe is not cheap and neither are the fittings - but they work very well

Ben-gee · Dec 11, 2020

Another vote for electric heating and more insulation.

Central heating in a garden outhouse...

junksamiad

PETE 123

junksamiad

SimonG

oz-plumber

gpbeck

Last Plumber

Murdoch

junksamiad

Murdoch

gpbeck

SJB060685

Plumbers Arms member

gmartine

king of pipes

Attachments

Brambles

Ben-gee

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