Heating & Boiler FAQs

A combination (combi) boiler heats water for central heating and provides hot water directly from the mains when a tap or shower is opened. It generally does not need a separate hot-water cylinder, so it can save space. Suitability depends on mains flow and pressure, the number of bathrooms and simultaneous hot-water demand.

A system boiler heats the central-heating circuit and stores domestic hot water in a separate cylinder. Many major components are built into the boiler, which can simplify installation compared with some older arrangements. It can suit homes with greater hot-water demand, but requires space for the cylinder.

A heat-only (regular or conventional) boiler supplies heat to the heating system and works with a hot-water cylinder, and usually a feed-and-expansion cistern or other system components depending on the design. It can be a sensible replacement for an existing open-vented system, but the existing pipework and controls should be assessed before changing system type.

There is no single best type for every home. The decision depends on property size, insulation, radiator demand, mains water flow and pressure, bathrooms, hot-water usage, existing system layout, available space and budget. A competent heating professional should assess the property and explain the options before a final recommendation.

Sometimes, but it is not always the best option. The change may involve removing a cylinder and tanks, altering pipework and controls, and checking whether the incoming mains supply can meet demand. The full scope and cost should be assessed before agreeing to a conversion.

Your postcode, property type, existing boiler make and model, boiler location, number of bedrooms and bathrooms, hot-water cylinder details if present, and photos of the current installation can help. A site survey may still be needed before a final quotation.

Package inclusions vary. Ask for a written quotation that identifies the boiler model, controls, flue and fittings, system cleaning or treatment, commissioning, removal and disposal, warranty conditions, and any exclusions or additional work. Do not assume an item is included unless the quote says so.

A straightforward like-for-like replacement may often be completed within a day, while system conversions, relocated boilers, difficult access or additional pipework can take longer. Timing should be confirmed after the installation requirements are assessed.

DomCom Heating welcomes domestic and commercial heating enquiries across its service area. Commercial systems vary significantly in scale and requirements, so provide the site type, system information and requested work to establish whether the project is suitable.

We cover Buckinghamshire and selected areas of London, subject to postcode and availability. Use the quote form to confirm whether your property is within our current service area.

We can discuss options from brands such as Vaillant, Worcester Bosch, Baxi, Main and Glow-worm, subject to model availability and suitability. The best choice depends on the property, budget, features, service support and warranty terms available for the specific model.

No. Warranty length and conditions depend on the model, manufacturer, registration, installation requirements, servicing and any applicable promotional terms. Confirm the warranty in writing for the exact boiler being quoted.