Should I replace my conventional boiler with a combi?

If yous have just bought a new abode, your existing banality has cleaved down or the banality that you lot take is over 12 years old, then you should peradventure consider a replacement. Combi boilers are fantastic, as they provide space heating as well as water on demand – you can practice away with the hot water tank.

If you have a regular heat-only boiler is it worth making the change?

Your existing heating arrangement

First of all, it is of import to establish the existing heating system you accept and the type of arrangement you are looking for. This will affect on whether or not a combi banality is appropriate to install in your abode.

cold tank

When talking about 'conventional systems', nosotros are normally referring to a oestrus-only banality, which has two cold-h2o tanks in the loft space and a hot h2o tank, commonly found in the airing cupboard.

A organization boiler is very much like a heat-only boiler, except you don't require the feed and expansion cold-h2o tanks in the loft.

A combi boiler, as discussed previously, works past providing hot water without the need for a hot or common cold water tank. Basically, if you turn the hot water taps on, the banality volition burn up and oestrus the water coming out of the pipes. Since yous don't need to store the hot h2o earlier you use it (i.e. in that location is no hot water tank), these tend to be considered more efficient.

What are the reasons for installing a combi boiler?

One of the main reasons for installing a combi banality is the fact you can do away with the water tanks and this obviously frees up a lot of space. This is particularly important in flats and small houses where infinite is at a premium. Imagine all of a sudden beingness able to utilise your existing airing cupboard for additional storage space. Y'all still need a space for the boiler of course, simply information technology is typically like in size to a standard heat-only boiler and could go in the same space.

Related to the previous point is the fact that the combi boiler doesn't produce and store hot water. With a regular boiler, hot water tends to exist produced twice a day, regardless of if it gets used or not – in the morning time and in the evening. At present patently this requires the boiler to burn down up to produce the hot water, and if for whatever reason it doesn't go used the h2o simply cools downward, which is a waste product of energy. Combi boilers simply produce the hot water when you need information technology (i.east. you turn a tap or the shower on), so evidently for many people this produces substantial energy savings.

>>> How much should a new boiler toll? >>>

Combi boilers are great when yous have relatively minor hot water demand at any one time. If you lot require hot h2o feeds in multiple outlets at the same time– say that y'all want to run two showers at the same time in the morning, and so a combi banality won't be suitable. In this case a regular or system banality might be more suitable.


The concluding signal is that with a regular boiler or system boiler one time you have used all the hot h2o, that is it; you'll need to wait until the banality fires upward and produces new hot water as per your programmer settings. With a combi banality you lot could in theory produce limitless hot water although the mains water force per unit area defines the output.

Obviously information technology is worth mentioning efficiency – a new combi boiler should exist effectually 90% efficient (as would a new system or regular boiler), so if your boiler is especially one-time you lot might want to install a new banality at this bespeak.  You can run some calculations to see if this might be relevant for you – you can learn more most it hither or talk to our partners over at Heatable.

When should I install a combi banality?

Yous can in theory change your heating system any time, only the best time to practise this is probably during a general refurbishment (provided the boiler is working okay!).  Conveying out this work when yous refurbish will assist minimise upheaval since things like running new pipes under floors are complicated if there is a nice rug in place! Calculation whatsoever new radiators to the arrangement will apparently make this a bigger job, as will a system conversion when yous move from a organization or heat-only boiler (with tanks) to a combi.

If you are carrying out refurbishment piece of work, y'all should also try and install as much insulation as you tin at the same time as installing a new heating arrangement – this will lower your gas demand since heat will leave the dwelling house more slowly and therefore yous should see even bigger free energy savings.

>>> How much should a new boiler price? >>>

We also recommend looking to install a boiler before the winter, since at this time there tends to exist a big rush on plumbers, which pushes the cost upwards a piddling – changing the boiler during the summer months should therefore be a footling cheaper.

The terminal point is related to positioning the new boiler – with regards to where the existing boiler and flue currently sit. If the banality is being replaced so the flue will take to sit on an outside facing wall, which may require physically relocating it. This volition add to your costs. A plume diverter may also need to be installed depending how close the current flue is in proximity to your local neighbours.

Companies like Heatable volition often also offer finance options, meaning that your new banality could toll you from every bit picayune at £10.fifty a month. You can visit them here for more details.

Condensing combi boilers

Condensing boilers are pretty much standard these days for all domestic applications – whatever banality you lot install now, be it combi, estrus only or system volition be condensing.

A condense pipe connected to a downpipe.

Condensing boilers are highly efficient and virtually are at present manufactured with an efficiency rating of 90% or better. They use heat in the waste flue gas to pre-heat the cold h2o going into the boiler, hence this high level of efficiency.

A condensing combi banality (like all condensing boilers) will have an additional condensing pipe that allows the condensed vapours to be drained away as the boiler is working. This shouldn't be a trouble as long every bit the installer tin adhere the pipe outlet to a drain, either internal or external. If this isn't possible and then the banality may accept to be relocated, which will add to the overall installation toll.

Combi boilers and flue gas rut recovery systems

A Flue Gas Heat Recovery System (FGHRS) works by using a farther estrus-exchanging unit to take advantage of the heat within the waste matter flue gases, which any boiler volition produce. This recovered heat is used to preheat the cold water entering the boiler, thereby lowering the corporeality of energy needed to warm the h2o up to the required level.

Fifty-fifty the most efficient boilers available on the market today are only ninety% efficient, as a result of oestrus lost in the waste material flue gas; even so the installation of a FGHRS on fifty-fifty a brand new boiler tin can help further bulldoze upwardly energy efficiency, helping you lot save money on your bills.

>>> What is the best brand of boiler to install? <<<

How much practice combi boilers cost?

At that place is a web log discussing the cost of boilers hither.

  • Straight swap with existing combi – starting £1,600 + VAT (labour & parts)
  • Combi conversion (going from estrus merely or system) – starting at £ii,500 + VAT (labour & parts)

Is it worth swapping to a combi banality?

If you have a small firm and you are already tight for space, so combi boilers are a fantastic solution. Also if you are just moving into a holding and volition be carrying out extensive refurbishment, then having a new heating system installed at this fourth dimension is platonic.

On the other hand, if you have a big firm with extensive hot water demand at whatever ane time, you lot may want to go for a system/regular boiler.

As well if you are on a tight budget, the organization conversion will add to the overall costs.

Installing a new banality

Are yous thinking about getting a new boiler? We take scoured the country for the best tradespeople, so that we tin can make sure we merely recommend those nosotros actually trust.

If you would like us to discover yous a local installer to install a new boiler in your home, just fill up in the form below and we volition be in touch shortly!