New Boiler Portsmouth: Gas Safe Installers & Quotes

Portsmouth is one of the most tightly built cities in England. 43% of households live in a terraced house and fewer than one in twenty in a detached one, according to the 2021 Census.

For a typical two or three bedroom terrace with one bathroom, a combi is usually the right replacement: no tanks, no cylinder, and the loft freed up.

Portsmouth at a glance

Water hardness: Every Portsmouth Water supply zone averaged hard (201 to 300 mg/l) or very hard (over 300 mg/l) in 2025, ranging from 267 to 315 mg/l as calcium carbonate. The four Farlington zones averaged 279 to 294 mg/l. Source
Terraced housing: 43.4% of Portsmouth households (37,361) lived in a terraced house in 2021. Only 4.5% lived in a detached house. Source
Energy ratings: About 50% of homes with an EPC in Portsmouth are rated band D or below (median score 69, band C), against 47% across England. Based on certificates lodged in the 10 years to March 2025. Source

Very hard water needs protecting against

Portsmouth Water's 2025 averages put some zones above 300 mg/l. A new combi should be fitted with a scale reducer on the cold main as well as a magnetic system filter and inhibitor. Ask for each to be named on the quote.

Without them, the plate heat exchanger in a combi can scale up within a few years.

Where the boiler goes

Terraces often have the boiler in the back kitchen, with the flue into a narrow side return or the alley. Flue terminals must sit set distances from windows, doors and boundaries, so a new model may need a different flue position or a plume kit.

Moving the boiler upstairs to free kitchen space adds gas pipe and condensate work. Get that priced separately.

Checking the quote

Does it include a flush, new controls, the flue, removal of the old boiler and registration with Gas Safe? You should receive a Building Regulations compliance certificate after the job. Compare prices with our new boiler cost guide.

Matching the boiler to Portsmouth homes

Victorian and Edwardian terraces

Bay-fronted terraces with a loft conversion and an en suite may need more hot water than a combi gives. A system boiler with a cylinder is the alternative, if you can find cupboard space.

Converted houses and purpose-built flats

Compact combis fit standard kitchen cupboards. In a block, check the lease and any rules about flue positions before choosing a model.

1930s semis on the mainland side

Semis in Drayton and Farlington have more room for a heat pump later. If that's likely, ask whether the new boiler's controls and cylinder could work with one.

Areas covered

Engineers who cover Portsmouth work across areas including Southsea, Fratton, North End, Copnor, Milton, Eastney, Hilsea, Cosham, Drayton and Farlington.

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Questions people in Portsmouth ask

Is a heat pump an option instead?

In a mid-terrace with a small yard it can be harder, but not impossible. Get a heat pump survey alongside your boiler quotes if you're unsure.

How long does it take?

A straight combi swap is usually a day. Changing from a regular boiler to a combi and removing the loft tanks can take two.

Sources

Also nearby: Boiler installation in Southampton, Boiler installation in Brighton, Boiler installation in Bournemouth

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