Average Labour Cost/Price to Fit/Install/Replace Central Heating
To clarify the following prices it is recommended that you read the article in the INFORMATION box below the PRICES…
(These prices are based on a tradesman’s rate of £150.00 per day and a labourer if required at £100.00 per day. This includes the cost of buying and collecting any materials, dumping any waste if necessary and any incidental materials they will need. The minimum price will usually be for a half day)
How Much Does It Cost To Fit/Replace Central Heating?
A new central heating system in your 1930’s three bed “other house” which is completely empty, with exposed floorboards. This will comprise a mains gas wall hung condensing boiler on a nice empty wall with a drain outside, 8 rads. with TRV’s, an insulated hot water cylinder with a thermostat, a three way valve (which allows for hot water in summer but not heating), plastic pipework “all round” (insulated downstairs), an insulated header tank in the loft, a programmer and a roomstat. All the original hot and cold water pipes not relevant to central heating are to be kept and everything will be delivered on site by the supplier.
This will take 2 men 5 days
Lift boards, hang rads, hang boiler, fit flue and drain.
Fit cylinder and valve, fit loft tank, lay pipework and insulation
Connect boiler, connect rads, chase walls for electrics fit programmer etc.
Connect cylinder, fit electrics, plaster over,
Commission boiler, balance system, refit boards,
Boiler and flue £825
Controls and valves £225
Cylinder and tank £150
Insulation and plaster £120
Tip and Fixings £45
Exactly the same job in your house with you and the kids living in it at the same time so no boards or carpets can be left up at night.
This will double the labour bill
A boiler change from your old wall hung one to a new wall hung one in the same position on the kitchen wall.
This will take two men 1 day, you will have to make good afterwards.
Boiler + flue £825
Fit TRV’s to 7 of your 8 existing rads. (this will leave the necessary by-pass)
This will take two men one day, they will probably drain the system down.
New chemicals £25
Change one leaking radiator for a similar sized one with a TRV in the same position.
This will take one man one leisurely day.
Rad, valves, pipe, tip. £125
If you want a new programmer or room stat fitted, the average heating engineer won’t do that, central heating electrics can be a pain. He can do it all from scratch with idiot-proof systems but adding things is difficult. You best get a sparks in. He will spend as long working out what’s there, as he does fitting the new stuff, so you can expect it to cost:
The Building Sheriff recommends Peter from gasplumb.com (in West London/Surrey/Middlesex) - he works on The Building Sheriff's own home!
(gas safe no. 529 102)
A Price Guide and Information Sheet on Fitting and Installing a New Central Heating
By definition central heating means a heat source in one place in the house and lots of connected heat outlets in the rest of the house. (In most cases this means a boiler and some radiators)
There are variations on this theme though, a boiler and underfloor heating, a heater and warm air ducts. Other types of heating such as electric storage heaters and individual room heaters/fires (using gas or solid fuel or oil or electricity) are not actually “central” heating.
The third part of a normal central heating system is the hot water cylinder or “cistern”. This is usually found in the airing cupboard and is not, as some people believe, a boiler. This “cistern” gets its water supply from the cold water supply tank which you will have found in the loft when your wife told you to go up there and find out what that scratching sound was and don’t come down till you have killed it!
Hot water from the boiler travels in pipes round and round inside the “cistern”, then comes out again and goes back to the boiler to be reheated. This internal pipework is called a heat exchanger; heated water transfers it’s heat to the cold water in the “cistern” without ever coming into direct contact with it. At no point does the water from the boiler and the central heating system mix with the water in the cylinder. If it did you would soon know about it. Central heating water is filthy black stuff, a result of chemical reactions between the different metals in the system (copper, steel, aluminium, cast iron, brass etc.) plus the chemicals we put in the system to help it work better.
So, you now have a “cistern” full of hot water. When you “draw some off” (plumber speak for turning on the tap), it leaves from the top of the cistern, cold water from the loft tank then enters the bottom of the “cistern”, gets heated by the heat exchanger and off we go again. Amazingly, it all works by gravity. As long as the water company can pump the water into your loft tank, it can then run down through the pipes, then (through you) into the drain, through the sewer, into the river and back to the sea. How does it get back out of the sea? I must have been away that day!
For your own and the environment's sake, the more efficient your system is, the better!
Fuel costs, ain’t going down! If you have a very old system, or you have just moved in and have some spare cash (I’ve never had any “spare cash” in my life, by the way), it will save you lot’s of money in the long run and you will be a lot warmer immediately, if you rip it all out and start again.
If you have decided to do this don’t be tempted to leave the existing radiators in place. They are 20 years old, they are inefficient, they might be clogged up, they might even be close to the point when all those tiny internal corrosion points actually break through and leak.
System Components and Design
Not all systems are fuelled by mains gas, which is the cheapest fuel option. (I didn’t say cheap, I said cheapest). The next most expensive is oil. Getting more expensive in order are, off peak electricity, on peak electricity, coal, LPG (propane) from a large tank, propane gas from those orange “bottles” you see outside caravans and in builders vans. So if that delightful little holiday cottage you are buying uses bottled gas, get the oil in!
There are 2 types, standard and combi. Standard ones sit on the floor or more likely hang on a wall and supply the radiators and hot water cylinder.
Combination boilers (combis) sit on the floor or hang on a wall and supply the radiators in just the same way but there is no hot water cylinder. This is because the combi boiler also acts like those old fashioned geysers which hung over the bath or sink in those black and white films with Alan Bates in, when no one had any money and everyone lived in a beastly little terraced house up north and wore pinnies and went to work at 4 o’ clock in t’ morning, (I’d better stop, I can feel a Monty Python sketch coming on)! In other words, the combi also provides instantaneous hot water, to all the taps in the house as well as mains pressure cold water to all taps.
Irrespective of which type of boiler your new system will have, by law your next new boiler will also be a “condensing” boiler. These are very efficient indeed because they utilise the (already paid for) exhaust gasses to also heat the water. Unfortunately, this causes a constant drip of hot water, which leaves the boiler via a thin pipe and has ideally to be taken to an external drain (though it can be taken to an existing “soil pipe” or a specially constructed underground soak away). This can be a problem in some situations and may mean the boiler has to be placed somewhere you don’t necessarily want it.
Flues, (the boiler’s chimney)
Very old boilers, which usually sit on the floor, have metal or asbestos piped chimneys or flues, right up to roof height either visible, or hidden in a defunct chimney stack. These are called “open flues” and the oxygen for the boiler’s burner is drawn from the room they are located in.
Then progress happened and boilers were made to be room sealed. The outgoing exhaust gases and incoming oxygen pass through the house wall directly behind the boiler via a metal biscuit tin sized contraption. This has to be shielded with a wire cage however because it gets hot. Many a builder has warmed his hands in the dead of winter on one of these, they are called “balanced flues”. The boiler, which can now also be hung on the wall can be sealed into a compartment if you wish, though how will you get to it again?
Then the future happened and fanned flues were invented. These are essentially balanced flues, which have a much smaller (usually 4” (100mm) alloy cylinder, sticking through the wall. They allow more versatility in boiler positioning as it can now be sited on a non outside wall with the flue pipe going round a corner or whatever, on it’s way outside.
Condensing boilers are so efficient and retain so much of their heat, that their fanned flues can be made from plastic! Imagine that, what will they come up with next? I’m just squirming with anticipation.
(Hot off the press, just invented, the micro-CHP, “combined heat + power” or cogeneration. This boiler, wait for it, also generates electricity and you can sell this to the national grid. I’m not sure about this but I was told by a bloke in the pub that this means you have to have an electricity pylon in your front garden but think of the money rolling in)!
Hot Water Cylinders
Get the biggest one you can fit in the available space, provided it has the maximum amount of sprayed on insulation possible. Don’t get one without insulation and try to fit one of those ludicrous red jackets on it.
Make sure the installer sizes each radiator correctly to each room. There is a quite complicated formula which considers room position, use, size, window area, floor type, etc. and tells him the heat requirement that particular room needs to keep you warm. It's all about BTUs!
If you are having normal looking rads. the chap will then look at the manufacturers charts to see which size of rad. will supply (just a bit more than) the rooms required heat input and he will then fit that one.
There are however some complications. The siting of the radiator is pretty important. It used to be the case that they were put under windows. The idea was that draughts would be warmed up as they came in. Not a bad idea. That was before double glazing, which supposedly doesn’t let draughts in. Also if you’re exceedingly posh and have floor length curtains, all the heat gets trapped behind them. Intended furniture positions are highly relevant, you don’t want a rad. behind the sofa, which will stop the heat, or behind a piano which will eventually bend and crack.
There are lots of variations in radiator dimensions, from 12” to 28” (300mm to 720mm) high, from 12” to 86” (2200mm) long, with a thickness of one or two heating panels each with or without convection fins.
This means that if a room requires say 7500 BTU (British thermal units) of heat per hour to keep you warm, this output could be happily provided by maybe 4 different sizes of radiator, or you could have two or three smaller rads. whose combined output meets the requirement. It is aesthetically advisable when you have multiple rads. in the same room to keep them the at least the same height, even if the lengths and thicknesses differ.
Problems will arise though. If you want trendy Swedish radiators you could climb up to change the light bulbs from, you won't get the size variations and the room might just be a wee bit cold.
(I thought the radiator section would only be a couple of lines long… it’s a game isn’t it)!
The more gadgets there are, the more efficient the system will be, the more money you will save.
How big is your house? If it's 4 floors and you don’t use the top one unless your “grown up” children descend on you again when they inevitably realize which side their bread is actually buttered on, it is sensible to “zone”. This allows you to turn on / shut off a whole floor with a flick of a switch.
If you go away skiing to Gstadt (bless you) every winter, it’s sensible to fit a frost stat. (or even a boiler energy manager). This turns your heating on (even if its turned off) when the temperature drops to 3ºC.
For the rest of us, the following should suffice….
A programmer which allows the heating to operate at different times on different days (weekends versus weekdays), or just sets the hot water to come on without the heating.
Thermostatic radiator valves (TRVs) on all but one of the radiators, these allow for different temperatures to be set in different rooms. You set the required temperature on a scale of 1 to 6, the radiator shuts down when your required temperature is achieved and opens up again when the room temperature drops. This goes on unnoticed as long as you want. Magic.
One radiator however, usually the bathroom, should always be a “bypass radiator” with no TRV fitted. This is because potentially with TRV’s, all the radiators could turn themselves off and because they are mechanical and not connected electrically to the boiler or programmer, the boiler and pump would not know this and just keep working. Very hot water being created and pumped round with nowhere to go is a potential bomb. It won’t happen, boilers have internal thermostats and release valves and systems have vent pipes but why trouble them?
A room thermostat which is best sited away from any radiator or direct sunlight, adjacent to the front door, where it’s likely to be a bit colder than the rest of the house.
It will control the whole house’s temperature irrespective of any TRV’s fitted. If this is fitted in a warm area (a kitchen for example) it will think the whole house is warmer than it actually is and turn everything off before the place has warmed up. If you have (two) different zones (i.e. the main living area and then everywhere else), it is essential to have a roomstat in each zone.
The reason why a roomstat is necessary even with TRV’s fitted is to prevent the boiler “over running” via the bypass if all the TRV’s have shut down, which is an unnecessary waste of fuel (remember the boiler won’t know the TRV’s are off). In this situation the roomstat will tell the boiler that everything is hot enough at the moment and it can go and have a nice cup of tea.
A hot water cylinder thermostat which will tell the boiler when the water reaches the temperature you require, which should be 60º C. This saves fuel and prevents scalding because without one, the domestic hot water will be heated to the same temperature as that in the boiler and central heating system, which could be 80º C and that will scald you, never mind the kids.
Questions to ask the installer during his quotation visit.
Anyone can design and install any type of system including siting and hanging the boiler BUT the person who connects the gas, must by law be “Gas Safe” registered and the person who connects the oil must be “Oftec” registered.
Connection will also include commissioning the boiler, testing the pipework which supplies the fuel (not the central heating pipework itself) and in the case of an oil boiler the siting and type of storage tank used and in both cases checking the siting of the boiler and its external flue. Regulations cover all these aspects and all must be complied with.
What type of pipework will you be using?
Plastic pipework is common nowadays, it costs more than copper but is much faster to install (and labour charges are far more relevant). However, it doesn’t look as nice so make sure the little pipes which emerge from the floor up to the radiators are still copper and also regulations state that all pipes within 1 metre of the boiler should also be copper.
Do you understand about secondary earth bonding?
It is almost certain that your central heating installer will have limited knowledge of this. If he installs new copper pipework he should make sure it is all connected together and with existing metal pipework. All this must be with special earth straps and cable, which is then connected back to the dwelling’s main earthing point.
The idea is this…. If any metal object (radiator, boiler, exposed metal pipework, hot water cylinder) suddenly becomes “live” for whatever reason and you are touching it and another metal object which is not live, (or are standing in a bucket of water), electrical current will flow through you and you will say “Ow”. If he has fitted the pipes which connect all these metal the objects together, with earthing cable, the other metal object will also be live and you can quite safely touch it without getting a shock. Don't try it though!
Current regulations state that in bathrooms (but not kitchens), everything that conducts electricity (metal bath, radiator, metal water pipes etc), should be connected together and then back to the dwelling’s main earthing point either directly or via the earth block of any electrical source such as a wall heater or shaver point or electric shower, (secondary equipotential bonding).
IF the whole house is converted to plastic pipework this is no longer necessary, in fact it may be detrimental.
Does you know the type of radiators I want?.... Do you?
Get him to show you three different supplier’s brochures. They all produce different designs of rads. as well as the different sizes mentioned earlier.
Are you sure the boiler is "man" enough for the job?
If he consults his formula he can add everything up (radiator outputs, allowance for heat losses from underfloor pipework, the hot water requirement), and make sure it is.
A 1930’s, three bed semi will need at least an 80,000 BTU/hour boiler. If it’s a big four bed house 100,000.
BUT a new four bed house can get away with a 60,000BTU boiler! That’s modern insulation regulations for you.
Will you be insulating the ground floor pipework (which is under the floorboards)?
Of course he should, why heat the foundations? This is a bit difficult though because the pipes run in slots he cuts out of the joists tops and he should be careful just how much wood he cuts out in order not to weaken the joists too much. (Ideally all cuts should be within 12” (300mm) of a support wall).
Decent insulation almost triples the pipes diameter which could be a problem. What he should do is add insulation between each pair of joists but this will drive him mad and “customer induced short term insanity” is a favourite reason to slap a grand on the price!
You don’t need to insulate pipes under the bedroom floors, heat loss from these will find its way into the rooms anyway!
A-Z of Job Pricing