Which boiler for our house?

Combi or system boiler

  • Combi

    Votes: 2 40.0%

  • System

    Votes: 3 60.0%
  • Total voters
    5
  • Poll closed .
heatingdilemma

heatingdilemma

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We are getting a new heating system but different plumbers are suggesting different boilers.

Our house will be a 4 bedroom, with 3 bathrooms. We are a family of 4, 1 due imminently, 1 is nearly 2 and my wife and i. One bathroom will be downstairs and is existing having an electric mains shower over the bath and the bath gets water from the current heating system. The other 2 bathrooms are planned to be upstairs and I suspect the downstairs bathroom won't be used for showers and baths once the upstairs ones get built. One bathroom will be an ensuite with a shower and one bathroom will be the family bathroom with a bath and shower.

We are still undecided as to what will be the set up for the bathrooms upstairs, thinking do we put an electric shower in for one upstairs and heating system for the other shower and bath. I just cannot see a time when all three bathrooms will be used at once for showers/baths.

This conversation has been had with the plumbers that have come round, all have suggested a combi boiler apart from one who has suggested a system boiler. I just fear we will be heating a tank of water with a system boiler for no real reason.


What are other people's thoughts? Are we better to go with a combi? Or a system?


Our home is 150 meters squared, will have 12 radiators and is 1/4 stone construction, 1/2 80s timber kit and will be 1/4 modern timber kit.

All thoughts welcome.
 
Depends - It all comes down to usage and what your mains can deliver.

Some larger houses/households can manage their use so one shower at a time is perfectly practical so a combi can be used and if electric shower are acceptable then again it can be managed. Others don't want that constraint and want to be able to utilise more than one or 2 outlets at the same time and that's when stored HW comes into it's own. Don't forget that when the kids become older, using one at a time may not be so easily managed.

Heating a HW store isn't really that much of a waste as the cylinders are highly insulated so heat loss is minimal.

The radiators aren't really a consideration, as long at the boiler will modulate quickly or can be range rated.
 
You need to know your incoming mains flow rate & pressure in order to make this decision, certainly if the choice is between combi or unvented cylinder. If your mains can't support the flow rate required for an unvented cylinder there's no point having one. If it can then with a house your size I'd suggest a cylinder is the better option. Modern fast recovery cylinders on a priority hot water setup will heat up in about 20 minutes and retain that heat very well so you wouldn't really be wasting energy
 
I would be suggesting a combi perhaps, with an unvented system.

Combi could be configured (if system boiler is not used) to supply hot water to the kitchen and utility, possible one other showering a cylinder to supply hot water to other wash areas

Number of radiators you have, you could go for a 24 or 26kW combi
When combi breaks down, your cylinder will still be able to supply how water
 
I didn't catch what you have at the moment, is the new system a complete new system? you have four opinions at the moment but ask for more to clear confusion when more options and opinions may or not help. I'll stick my oar in.

If you have a CW storage cistern in the loft and a hot water cylinder, keep the cistern and upgrade the cylinder and fit a system boiler, with three bathrooms and it's stretch to use a combi although the electric showers do give backup if the combi breaks down.

Make sure a new or the existing cylinder has an immersion heater.

You certainly could use a combi and a cylinder and there are advantages to that but that depends on the layout of the house.

Get a heat loss and make sure the system is designed so that a heat pump can be fitted later if it's a new system.
 
System boiler with unvented & secondary return.

If your mains pressure and flow rates are rubbish then it's neither good for a combi nor an unvented.

If this was the case and you have the room then you could fit a booster pump with break tank.
 
Have you looked at heat pumps? They're a mature technology now, and the government are paying huge grants towards them - they're essentially free.

Hopefully I won't just have turned your thread into one where all the Daily Wail readers start ranting about them not working, it's all a conspiracy etc.
 
At the very least, ensure the system is suitable to be changed to a heat pump later, with low flow temperatures (= big radiators), which will also allow the gas boiler to run more efficiently anyway. Also have the gas boiler fitted somewhere close to a good place to put one outside, to minimise the disruption when it's a sensible time to change.

IMO it's quite likely that gas will at some point be taxed more and electricity less as an incentive to change over.

As with electric cars, the subsidies and tax advantages will be withdrawn as they become more normal. We're probably at peak-subsidy now, at a whopping £7500.
 
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