Understand the differences between combi, system and heat-only boilers, plus the key things to consider when comparing Vaillant, Worcester Bosch, Baxi, Main and Glow-worm.
The right choice depends on the building, hot-water demand, incoming mains supply and existing heating layout.
A combi boiler provides central heating and heats domestic hot water on demand from the mains, usually without a separate hot-water cylinder.
Consider if: you want a compact system and the mains supply can meet household demand.
A system boiler heats the heating circuit and a separate hot-water cylinder stores water for use around the home.
Consider if: hot-water demand is higher or the property already has a cylinder-based system.
A heat-only boiler supplies the heating system and works with a separate hot-water cylinder and system components configured to the property.
Consider if: you want to retain a compatible existing system rather than convert it.
These are general descriptions, not a ranking. Product ranges, warranties and availability vary by model and change over time.
Vaillant offers domestic heating products including combi, system and heat-only boilers. When comparing models, look at output, controls compatibility, dimensions, efficiency information, servicing arrangements and the exact warranty terms.
Ask which model suits the property rather than choosing by brand name alone.
Worcester Bosch supplies domestic boiler ranges and heating controls. Compare the model's output and hot-water performance, controls, installation requirements, warranty eligibility and service support for your area.
Confirm the specific warranty conditions and any registration or servicing requirements in the quotation.
Baxi offers heating products across different property and system requirements. Compare the exact model's size, output, controls, installation needs, warranty terms and ongoing support rather than assuming all models offer the same features.
Main is a boiler brand within the Baxi group. Its available models and specifications should be checked against current product documentation and suitability for the existing system.
Glow-worm offers domestic heating products across different system types. When comparing an option, check the model specifications, controls, warranty eligibility, service arrangements and suitability for your property's hot-water needs.
Compare the total installed price, model and output, controls, expected hot-water performance, warranty terms, servicing requirements, parts availability and the installer's written scope. A properly specified installation matters as much as the badge on the boiler.
Boiler sizing and installation must follow applicable regulations and manufacturer instructions. A qualified heating professional should assess the property before recommending a specific system.
Send your postcode, current boiler details and a few photos if available. DomCom Heating can then confirm the next step and whether a site survey is needed.
Request a boiler quote →