*this is going to be very wordy but I will try and give as much info as possible*
As a surveyor the first question I am most commonly asked is: What is Type of Boiler is Best? and usually every customer is under the impression that the best type of boiler is a Combi Boiler. My answer is always: well that depends….
Combi Boilers are fantastic for families or people who do not use much hot water, as they will only heat the water they use as they use it.
So for customers who would only have 1 shower a day (using on average 60-70ltr of hot water/ day) this is fantastic as they won’t need to heat a full 120ltr hot water cylinder. In the long run this can save a fortune on heating bills and also on water bills.
It can also save a lot of room as the system will no longer need a hot water cylinder or storage tanks. Freeing up space for that walk in shower you’ve always dreamed of.
However Combi’s do have their drawbacks…
Firstly, most combi boilers only like to do one thing at a time. For example: they cannot heat your hot water and your radiators at the same time. This is fine if your home is well insulated, however if you live in a cold, solid wall, house and someone decides to take a nice hour long shower you will most probably be sat downstairs shivvering.
Secondly, depending on the size of the new combi boiler and how good your mains water pressure is, it could struggle to run more than one tap at a time. This is because a combi boiler uses the same incoming mains water as the rest of the house. So the total water pressure will be shared out between taps like a cake; and the closest taps will get more cake/ pressure. (Not a problem if you only have one bathroom, as long as know one flushes a toilet or the washing machine kicks in).
Finally, if a current system is an open vent system (is there a header tank in the loft? If so it is an Open Vent system) then installing a pressurised system- such as a combi, will increased the pressure. No installer can guarantee how your system will react to this increase in system pressure and there is a risk of it causing leaks on your existing pipework and/or radiators. Most companies would not cover you under their public liability if this happens and causes damage. However the savings may out-way the risk.
Before you go ahead with an installation make sure your surveyor has explained all of the Pro’s and Con’s to make sure a combi boiler is right for you and your home before you take the plunge.
The alternative is a Regular or System Boiler.
A Regular Boiler is an open vent (with a header tank) system that will not increase your system pressure. A System Boiler is a sealed system (pressurised like a combi- same risks) where the pump is built inside the boiler.
Both of these types of boiler will mean that the customer keep their hot water tank. Now as I said before if a customer doesn’t use much hot water a combi boiler could probably be a better choice for them. However, if they use lots of hot water or have more than one bathroom the opposite is usually correct and it is best to keep the hot water tank.
Modern cylinders can heat up faster and hold their temperature for longer. Meaning big families can heat one large tank of hot water for everyone to use and it not cost the earth. It also means more than one person can potentially use hot water at the same time without causing a full scale row (great for teenagers!).
Regular or System boilers are also (generally) cheaper to install than combi boilers. So you have to take into account how long you will live in the house and how long it will take for you to save the difference. If not you will be paying extra for someone else to enjoy lower fuel bills.
There are of course drawbacks to this as well…
Regular boilers still rely on a header tank and can be prone to issues with air. A good installer will do everything to reduce this as much as possible, but there will probably still have 1 radiator that needs bleeding every month.
Also, Open Vent hot water systems can have poor water pressure from the tank, this can make having a good shower very difficult. This can be fixed by installing a Shower Pump- however these can be noisy. Or a Power Shower- these can be expensive.
If a home has good water pressure a customer could also consider an un-vented cylinder for mains-pressure-stored-hot-water, these however cost about the same as a boiler installation. But they are amazing if there is good water pressure, and a good bank balance (Worcester-bosch’s Greenstore is my top pick).
So your still non the wiser?
Choosing the right boiler is a big decision, and not one to be made lightly. Yes you could buy a combi boiler and it will of course save you money compared to the old 60% efficient Monster-Boiler in your pantry. But what if a Regular Boiler could have saved you just as much on your bills and cost you £1000 less?
That’s where a surveyor comes in. It’s their job to advise you on the best product and give you as much information and advise to help you make an informed decision.
Your surveyor should concentrate on what system is best for you… Even if that means they sell you a cheaper system and make less money.