Do I need a plumber or a heating engineer?

Either. Traditionally a plumber dealt with most jobs related to heating and plumbing, including guttering and bathrooms, while a heating engineer dealt just with the heating system. But nowadays the trades aren’t all that different — although there are still plumbers who specialise in areas such as ornamental leadwork, etc.

At what stage of a self-build is a plumber needed?

On new builds, the requirements are for such high standards of energy efficiency – with the heating system being the key component – that architects and designers bring in engineers at the drawing board stage. Often the house plans will be sent to the manufacturer to design the system, which costs around £100-£200.

The design used to be about the right boiler, but now it relies more on renewables as it’s becoming hard not to install them to meet regulations.

What about renovations and extensions?

Here the issue is usually more about resizing the boiler as the home’s insulation levels may have been upgraded, and the owners might want to change to underfloor heating or add solar thermal panels. The radiators, which might now be oversized, also need to be reassessed.

I want the latest technology, but the installer wants to use products he is comfortable with…

Seven out of ten times, the installer will select the boiler type and equipment for the house, but self-builders and renovators are doing a lot more research now. There are a number of bodies offering good independent advice on their websites, such as HHIC ( Also, Worcester, along with a few other manufacturers, will give fairly independent advice as it offers every type of technology. Whatever products you specify, the installer must have experience with them, though; most manufacturers have a list of recommended installers on their website.

(MORE: Your Plumbing Problems Solved)

How can I vet my plumber before hiring him/her?

For boilers, you must check with the relevant bodies (i.e. Gas Safe or OFTEC) that the installer is registered, but it can be trickier with other equipment. For renewables, check the MCS (Microgeneration Certification Scheme) register — as if you are to receive RHI payments, the installer and equipment must both be certified. If a manufacturer recommends the installer, they will usually be good as they will have had specific training — and the manufacturer won’t want any grief from unhappy customers!

(MORE: Using Renewables – Your Questions Answered)

Who should perform the heat loss calculation?

Plumbers and engineers will have learnt how to do heat loss calculations during training, but they might not put this knowledge into practice, instead relying on their experience to judge each situation. There are, however, independent bodies who will be able to produce detailed calculations for you, and many manufacturers also offer this service free of charge.

What common problems emerge after installation?

One of the biggest issues we’re seeing is where the existing central heating system doesn’t get flushed out — which needs doing on every boiler installation, with chemical inhibitors added. This takes half a day, so the installer might not include it in the quote, pricing low to get the job. If the system then has sludge, it reduces its life expectancy and efficiency.

How can I check the work has been done properly?

Every new boiler carries a benchmark checklist. Get hold of a copy and go through the list with the installer, asking them to demonstrate they have completed all of the tasks.

Is a boiler service vital?

We do like to see boilers annually. Combustion problems are unlikely, but the engineer needs to check that none of the components need changing due to wear and tear, that the balance of combustion gases is correct, and that the heat exchanger is clean. This ensures optimum efficiency and lifespan, and costs around £100.

(MORE: Boilers Guide)

What do plumbers cost?

Expect to pay around £200 a day. A boiler replacement takes one to two days and, including the boiler supply, costs in the region of £2,500-£3,000.

How Can I Ensure a Good Working Relationship?

Communication is the biggest issue. Be vocal at the outset, to ensure all your needs are met. Also, get the job description written in full and check it’s all included in the estimate.

Our Sponsors