Best LPG Boilers: Read BEFORE Upgrading [Small, Med & Large Homes]

Looking for a new BOILER?  Heard they are phasing out certain other boilers?  Then LPG boilers are for you – in this guide we are going to run though:
  • What size LPG boiler you will need
  • Whether you need a Combi, System or a Regular Boiler
  • LPG boiler prices & installation costs
  • The best LPG boiler for Small, Medium & Large Properties

What KW LPG Boiler Do You Need?

This is typically the bit which catches most people out: a) because manufacturers put no effort into explaining the kW output in laymans terms for the average homeowner and  b) they always over emphasize buying a bigger boiler than you actually need  A kW [kilowatt] is 1,000 watts. LPG boiler manufacturers, infact all boiler manufacturers, use this when talking about output power.  LPG Boilers come in 3 separate groups
  • 24kW – 27kW
  • 28kW – 34kW
  • 35kW – 42kW
I know what you’re thinking, could they not just name boilers after the number of bedrooms a property has, like 3 bedroom property boilers, 4 bedroom boilers – you know, that sort of thing.  I agree it would be easier on the surface but the reason they can’t is, all properties are different. There is no standard size, for example, for a 3 bed house.  Then add in the fact that bedrooms have no real bearing on the number of radiators and hot water demand from bathrooms either and you run into a ‘’boiler grey area’. So in this guide we are going to straighten everything out. 

The Solution

The most simplest way to determine the exact boiler size you require is with a few clicks over at HEATABLE. Its as simple as:
  1. Click here
  2. Answer just #5, multi choice, clickable questions [takes around 30 seconds]
  3. Get to see FIXED prices, onscreen, and you’ll also get next day fitting!
Heatable are the UK’s biggest and best boiler comparison site, and they work with all the big boiler players, meaning you’ll find a knock out deal in less than 90 seconds, with no personal details required. We like them as there are no annoying ‘calls backs’ or prices that are emailed to you – just simple FIXED prices shown on screen. They also offer finance which your local installer isn’t going to be able to.  I quickly filled out their online form and found I could get a Worcester Bosch boiler, which when fitted through them comes with a 10 year warranty – all for well under £2,500. My deals is here:

Choosing your Boiler

We have put together the following guideline below, which should help:

Property Size                    |     No. of Bathrooms    |     No. of Radiators    |     kW

Smaller [1-2 bedrooms]                        1                               10 or less                24kW-27kW

Mid Sized [3-4 bedrooms]                    1-2                             8-15                        28kW-34kW

Large Homes                                          2+                             15-20                      35kW-42kW

As we said above it is a guideline, if you have ‘extra’ living space like a converted loft, conservatories or ensuites and shower rooms, it’s all going to play a part in the decision making process.

LPG boilers are simple – they heat and deliver hot water. So if you have a bigger demand for hot water you’ll require a bigger boiler to service that demand. 

What Kind of LPG Boiler Do I Need?

Easy to choose from as there are only 3 types of LPG boilers:

  • Combination Boiler [‘Combi’]
  • System Boiler
  • Regular Boiler

If you are looking to save a few quid, then our advice is stick to the boiler ‘type’ that’s already installed in your home. Changing would require upgrades to the unit itself, flues, pipework and maybe where it’s housed. 

With that said, if your boiler does not have sufficient power, in the first place or you have had an extension – then upgrade. But you don’t necessarily have to upgrade boiler type from say a combi to a system you’ll only need to ‘upgrade’ in kW. So say from 24kW to 28kW. Happy?

It’s horses for courses, so let’s go through the different boiler ‘types’ in more detail so everyone is on the same page, as not to throw a spanner in the works but there are instances when an upgraded boiler type [combi to system boiler for example] could be beneficial…

LPG Combi Boiler 

Combination boilers heat water on demand, i.e ‘there and then’ – exactly when it’s required. So with a combi you won’t have a cylinder or hot water tank [often located in your loft]. So the positives are space saving.  

The ‘negatives’ of combi boilers is, in terms of hot water, you could see a drop off during usage. Run a long shower and some taps whilst the central heating is on and you could see a drop off. 

Typically what you see fitted into homes with 1-4 bedrooms are condensing LPG boilers, these are without doubt the most popular. And with good reason as they are fairly well priced and 9 times out of 10, they are all you will need.  

Do you have more than 4 bedrooms? [or greater hot water demand than average, i.e 2 bathrooms?]

Ok, in that case you are probably going to require a system boiler, as a combi won’t be able to keep up with the demand. Or you’ll have to install a HUGE and expensive combi just to keep pace, which could be unnecessary. 

A system boiler will heat water up in advance ready for usage later on, meaning you’ll have no issues with heating your home, running taps and having 2 showers running at once.

LPG System Boilers

System boilers are more suited to larger properties [2+ bathrooms] as they have a hot water cylinder. So that means you will be able to run more than 1 shower, taps, plus your heating all at once. 

The ‘draw back’ of a system boiler is housing the cylinder, you will obviously need space for that. 

Do I Already Have a System Boiler Installed?

Simple  – do you have a boiler and cylinder but no hot water tank? 

If you only have a boiler and cylinder you currently have a system boiler, so if you are just looking to replace that, crack on you’re squared away. 

But just make sure you have checked the loft for a hot water tank before saying you haven’t got one…! Because if you have got a hot water tank [that is still connected up and working!] you have a ‘Regular’ boiler. 

Regular LPG Boilers

A regular boiler has both a cylinder like a system boiler but also has a hot water tank. So in terms of total space, this type of boiler requires the most. 

So if you have a boiler, cylinder and a hot water tank you currently have a regular boiler. 

Happy with the set up you currently have – then crack on, you simply require a new regular boiler. [provided the cylinder and tank are all in good working order] 


Now let’s say you wanted to do away with the hot water tank, for whatever reason [you could have converted the loft and no longer have the space] you could then ‘upgrade’ to a system boiler. 

It will mean still having a cylinder but it will also mean you can do away with the hefty hot water tank.

The upshot of upgrading means changes and changes and alterations usually means [not always] more money. But if it saves space it could be well worth it and you can get deals here on system boilers with next day fitting included.

The Best LPG Boilers in the UK

With LPG you’re safer staying with the better boiler brands. Alot of time you see these cheaper brands offering LPG boilers and they simply aren’t worth it in our opinion.  Ask any heating engineer which brands they are called out to repair and they will tell you it’s all the low end stuff.  Their parts just don’t have the longevity or reliability and as such the manufacturers don’t offer the warranties on them.  To save a couple hundred quid going for a cheaper brand wont stack up over the lifetime of the boiler. It all comes down to warranty. You can get a fixed price deal from an online installer like HEATABLE for an LPG boiler and get a 10 year warranty on the best boiler brands there are. 

The Top #7 Best LPG Boiler Brands:

  • Worcester Bosch
  • Viessmann
  • Ideal Boilers
  • Vaillant
  • Baxi
  • Potterton
  • Vokera Boilers

Best LPG Combi Boiler for Static Caravan

The best LPG combi boiler for a 1-3 bedroom static caravan is the Worcester 28 CDI Compact which is 24kW.  Compact enough to fit into a cupboard so it can be ‘hidden’ away but powerful enough for the hot water demands for 1 bathroom.  Obviously with Worcester Bosch you are getting one of the UK best boiler brands being A rated and extremely efficient but they also come with longest warranties. Grab a fixed price here

LPG Boiler Prices

Each brand has different models all with confusing names and associated numbers so let’s break down the best ones, what they offer and the price of them. 

LPG Combi Boiler Prices

Model                                     |      Output (kW) |        Boiler Prices Worcester 28CDI Compact               24                         £1,200 Vaillant EcoTec PRO 28                    24                         £1,150 Baxi DuoTec 28                                  24                         £1,300 Worcester 34CDI Classic                 30                         £1,350 Worcester 38CDI Classic                 30                         £1,450

LPG System Boiler Prices

Model                                     |      Output (kW) |        Boiler Prices Worcester 24I                                       24                         £1,150 Worcester 27I Compact                     27                         £1,250 Ideal Vogue S32 GEN2 LPG               32                         £1,200 Vaillant EcoTec Plus 630                    30                         £1,350

LPG Regular Boiler Prices

Model                                           |      Output (kW)       |        Boiler Prices Worcester 27RI                                              27                           £1,050 Worcester 30RI Compact                            30                           £1,150 Worcester 40CDI Regular                            40                           £1,750 Vaillant EcoTec Plus 438 – Open Vent      38                           £1,500 *cheapest prices taken from PlumbNation or Travis Perkins*

LPG Boiler Installation Cost

Installation costs will vary across the UK and as such try and grab a minimum of 3 quotes from local installers and make sure those quotes are written quotes.  As what tends to happen is engineers get in and then find they have to ‘chase pipes’, or move something etc; it’s actually more common than you’d think. We recommend getting a FIXED PRICE deal from Heatable, the cheapest online boiler installer. They offer the best deals for boilers and fitting all in one fixed price.  Labour After the boiler unit, this is the next biggest expense and whilst you should only use Gas Safe engineers, labour rates of those engineers will vary. Gas Safe engineers in London will roughly charge double, when compared to the rest of the country. Infact in some areas of London engineers will pay for £30+ a day in parking tickets alone!


If you haven’t got a fixed price from an installer then you could run into problems. New boilers could require different pipework if it’s changed [even slightly] on the new boiler. You could also require new controls, if so then that’s extra and possibly unquoted for.  Do you live in a hard water area?  A limescale ‘descaler’ is a must if you do. It reduces the build up of limescale which can track through your boiler and starts to damage parts very quickly. Same with a boiler filter. If you have old radiators and an old system, then chances are there could be a build up of sludge.  A system clean could be required and is highly recommended then fitting a system filter after will help keep everything running smoothly. If this hasn’t been quoted for then add on another £200.  

Installing LPG Boilers

We have mentioned about only using Gas Safe registered engineers. This is now an industry standard.   But LPG boilers require a further certification that’s called CCLP1 PD for residential property. There aren’t as many LPG gas boiler engineers as ‘standard’ engineers.  Our recommendation is don’t mess about here, getting a fixed price for a boiler, which can be fitted next day, with a 10 year warranty coming with a system clean, system filter all thrown in should be priority number one. Get an onscreen quote from HEATABLE in 90 seconds.