Welcome to Struction

Hot water cylinders

There are essentially only 2 types of cylinder systems: Vented and Unvented. However, within those systems, there is a myriad of different types, brands and energy driven setups for you to consider, or are specific or necessary to your particular situation.

What’s the difference? The key difference between the 2 systems is a vented system is supplied from a cold water tank or cistern and works primarily on gravity for its power (water pressure). This can then be boosted by pumps when necessary - like for a shower – or can be boosted for the entire hot water system as long as it doesn’t outpower its supply.

Unvented systems, on the other hand, are powered by the mains so you get equal pressure/flow from your hot and cold. Except in very particular situations, there is no need to boost this system but there are requirements that have to be met for this system to work correctly.

We can be on hand to visit and inspect your setup and requirements and advise you accordingly.

What boiler is right for you?

There are many boiler types and they can use a variety of different fuel sources. We won’t go into many of them but focus on the 3 main types of gas boiler and we’ll touch on electric boilers.

The 3 main gas boilers are: System, Combi and Regular boiler. The system boiler is one that not only generates hot water for your central heating and hot water cylinder, but it will also power it around your system without the need of external pumps. These are efficient, but they are not the most efficient of the 3. Why they may be considered better in some cases is that combined with an unvented cylinder you get mains pressure on your hot water so showers at any level of your property work well. These boilers are best used on sealed systems and not gravity-fed.

The most efficient of boilers are the Combis. These heat your house and generate hot water on demand so there is no wasted energy. They do have limits on how much hot water they can generate and pump out, so large houses with many bathrooms may struggle when demand is high. However, in most cases this just means a family establishes a routine that works under that system.

The last of the non-electric boilers is the Regular boiler. This is very similar to a System boiler, but it has fewer working parts and so requires external pumps and other controls to end up as the same. These are cheaper and are usually installed alongside a vented cylinder under a gravity-fed system. This setup is the least efficient and there are regulations/conditions in place that have to be met if there is no alternative but to maintain this rather dated system.

There are electric versions of these boilers and, under perfect conditions and energy prices, these can rival gas and oil boilers in cost efficiency at least. The technology is still improving and we are more than qualified to install one of these if your situation requires it.

The evolving world of energy efficiency.

There is a regulation in place that is required for all Combination (Combi) boilers. This governmental legislation is what’s called “Boiler Plus” and it requires one of 4 things which we’ll briefly explain.

There is no particular order but let’s start with Smart controls as they are the ones that will easily satisfy this requirement and a type of system we are all becoming used to in one way or another. What these controls do is learn about your requirements and adjust accordingly in what they consider to be the most efficient way. In truth, they work best with boilers that have what's called “opentherm” technology, but they are also remotely controllable so they can add a real level of convenience to your heating scheduling. We recommend Nest and we are part of the Pro Installer program which entitles you to longer warranties when supplied and fitted by us.

Next up is “Weather Compensation”. This system monitors the outside temperature and then modulates the heating flow in an optimised way so that the least amount of energy is wasted. It uses sensors to do this and prevent your heating circuit from “cycling”. Cycling isn’t good as it means your boiler just goes into max mode to reach your desired temperature and then turns off, then when it drops below that target it maxes again and so on. Predicting temperatures means your boiler can work more efficiently and last longer.

Load Compensation is next and this works the same way as Weather Compensation, only it measures the inside temperature and your demand and then modulates the boiler. The fundamental difference between the two is that Weather Compensation is proactive, and Load Compensation is reactive.

Lastly, we have PFGHRD (Passive Flue Gas Heat Recovery Device). While all modern boilers increase their efficiency by condensing flue gases back into liquid and then using the heat from that product, Passive Flue Gas Recovery goes a step further and uses a heat exchanger to claw even more energy back from your flue gases. Some boilers even have this system built in so there is no need for additional measures to be compliant.