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Priority Hot Water

What is Priority Hot Water?

In the old days, it was common for heating engineers to set up your central heating system with priority hot water. What this means is that should you have your heating on, if you turned your hot water on at the programmer or your cylinder cooled down and needed heating up again, your heating/ radiator circuit would be turned off and all the heat would be diverted over to the cylinder in order to re heat it. As time went on this changed and engineers stopped using this method and instead started setting up the system where both radiators and the cylinder could be heated up simultaneously and independently in what’s commonly known as S- Plans and Y- Plans. This was largely down to inefficient cylinders which weren’t very well insulated, they lost their heat very quickly and could take in excess of an hour to heat up, by which point, on a cold winters day, your house has become freezing cold because the radiators have been off while waiting for the cylinder to heat up. Modern cylinders are incredibly well insulated and retain a lot of the energy that has been put into them to heat the water and have taken me by surprise. I recently went on holiday for a week and turned off my hot water so my boiler wouldn’t come on while I was away, when we returned 7 days later the water was still hot enough to have a shower!! 

Recently, hot water priority is making a come back. Coupled with Open Therm technology and an Intergas Boiler, priority hot water gives the ability of your boiler to have 2 different flow temperatures, meaning you could have a flow from the boiler of 75 degrees for your hot water to allow for quick re heat times and a modulating temperature with open therm for your radiators, not only does open therm keep your house at a more constant comfortable temperature, but it also allows your boiler to do what it was designed to do and stay in condensing mode, dramatically increasing its efficiency and saving you money on your heating bills. This has been made possible by new rapid recovery cylinders with extremely quick re heat times, some as little as 5 minutes!! The other advantage of these rapid recovery cylinders is that bigger houses or properties with high hot water demand now no longer require giant 300+ litre cylinders and a cylinder that’s around 170 litres would be the same equivalent. The cylinders are so quick at heating up that as your using the water, the cylinder is heating up behind it. This not only saves on space needed for the cylinder, but also saves you energy and decreases your gas bills as you no longer need to be heating 300+ litres of water all at once and keep it hot.

There are no official figures available on exactly how much and what percentage a condensing boiler that it set up correctly to fully condense will save you. This is due to the amount of variables from house to house eg 

  • how well insulated it is
  • does it have doubled glazing? 
  • how often the occupants have the heating on 
  • how long the occupants are at home 
  • how often they open and close doors
  • how many radiators they have
  • how big the radiators are
  • how cold it is outside 

The list goes on. The only rough figures I have are from conversations with my customers who are pretty hot on keeping an eye on their energy bills and they tell me the comparison between their gas bills with their old boiler and the new condensing one which I have set up and adjusted correctly to achieve maximum condensing from it. An example of one customer where I removed their old 30 year old boiler and converted their old gravity hot water cylinder which had no lagging or insulation, over to a new condensing combi literally halved their gas usage the following year. Another customer who was already quite savvy when it came to energy saving, went from a condensing boiler and standard cylinder with on/off room stat controls to a newer condensing boiler and priority hot water ultra fast recovery cylinder with open therm NEST smart thermostat for central heating, made a saving of 32% the following year.

Priority hot water is most definitely the way forward, both for heat comfort in the home and saving money on your energy bills, please get in touch with MD Plumbing and Heating if you would like to know more and are interested in getting it installed in your home.