Tips for selecting the best boiler for the job

You know how to install a complete heating system, but do you know the best possible boiler for the job? Here Graham Collins, Training Support Manager at Baxi Heating guides you through his tips to boiler specification.

When you first visit your customer, never assume that the current system is the best one for the job. Boiler choice is as much about meeting the householder’s needs as it is the property itself. So, before you replace like-for-like, we suggest you ask the following questions so you can make the best possible recommendation for the heating system:

  • If an existing installation, what is the system and boiler type, and does it currently meet their needs?
  • How much hot water do they need?
  • What is the heating requirement?
  • How will the building type affect the choice?
  • Are there any plans to extend the building or change its use?
  • Will the customer’s budget restrict the options available?

All of these factors will affect the boiler and wider system choice.  With this in mind, here are some common scenarios and my recommendation for each.

Small property

A property with an average of two rooms, for single or dual occupancy and with one shower room will require a relatively small heating output and need a compact, cupboard fit boiler that won’t take up valuable space. The ideal choice would be a Baxi 224 combi boiler with a 24kW hot water output and 21kW heating output (condensing). It has a 3-year warranty and is perfect for a customer on a lower budget with a relatively low demand for hot water.

A two or three-bed property

For a two or three-bedroom 1940s property for a family of three with one bathroom, I would suggest the Baxi 400 combi range. A 24 or 28kW output should be ample but remember the flow rate: a Baxi 424 offers 9.8 l/m, whereas a 428 offers 11.5 l/m. Both of these boilers have a heating output of 21kW. Where the customer prefers a bath to a shower the 28kW would be better as they could fill the bath quicker.

A three or four-bedroom property

So how about a three or four-bedroom newbuild property, with two bathrooms? This would require a larger boiler output in order to meet the heating and hot water needs of the whole house. We would recommend the Baxi 636 combi, with a seven-year warranty. The Baxi 636 Combi delivers 15 l/m at 35 degrees C temperature rise and has a heating output of 26kW, which would be ample for a well insulated newbuild home.

A large property

A moderately insulated larger dwelling with four bedrooms and two bathrooms, for a family of five, would be different again. For this family, the best solution would be a heat-only or system boiler, as they could all want hot water all at the same time.  A Baxi 624 Heat with a 250 litre Heatrae Sadia cylinder would be a great option. If, however, there is only one shower, you could opt for a Baxi 836 Combi with a flow rate of 15l/m and this boiler is supplied with a 10-year warranty and comes with a magnetic filter in the box.

Although there are many potential options to consider, understanding the best solution for each job takes time and ultimately comes down to experience. While this isn’t an exhaustive list of options, it does provide a guide and is designed to get you thinking about the wide range of solutions that could meet your customer’s needs.

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