Since this guide is aimed at consumers, we have to give you a full overview. As with any device, there are downsides to operating a combi boiler – you can’t run two showers or two taps at the same time. There is a limit to the water flow that it can produce and only the tap closest to the boiler will produce a meaningful stream of hot water. If you open another tap at the same time, you’re lucky to get a fine trickle of warm water. Thus this option is not suited for a large family that needs to run several showers in the morning. Otherwise you’d have to queue up and risk being late for work or school. Another downside is that if it breaks down, you will have no hot water because there is no cylinder to heat it up.
Nevertheless, during the last few years, combi boilers have established themselves as market leaders for domestic boiler installations. As the household sizes keep reducing globally, there’s less and less demand for heating systems that can produce multiple streams of hot water.
Combi are considered low pressure boilers. If your water mains is weak, you may struggle getting a steady enough stream of hot water. If this is the case, make sure you mention this when getting a boiler quote or survey. It’s still possible to install a combi, however, you are likely to need an additional central heating pump to help the low mains pressure and ensure you get steady shower.
If you have an older system with a tank in the attic (an open system that relies on gravity rather than water pressure), the pipework may be too dodgy to handle a new heating system. In this case you may have to consider a complete overhaul involving new copper pipes taking your property into the 21st century and making sure the pipes are reliable enough to handle pressure.
All these downsides of combi boilers can be easily overcome apart from the demand issue. If you know you need simultaneous hot water from multiple taps or showers, then Regular or System is the way to go. We can help you with that too, just talk to our advisor when you discuss your boiler quote.