Why do some houses take time to heat the water while others have it near instantly?
In: Engineering
There are multiple factors, however the largest I’m delay between activating the hot tap and hot water flow is actually the type of pipe. See as water flows through the system it has to pass through a lot of relatively cold pipes and thus dumps a lot of heat energy into that pipe. This means that until that pipe is close to as warm as the water you won’t get any hot water from the tap. Now, the difference in timing comes from pipe material. More modern synthetic piping like pvc absorbs much less heat as compared to the more traditional copper pipes so the water will come out hot in the synthetic tubing faster.
It’s also slightly dependant on your water pressure. Houses with higher water pressure will have a faster flow rate. Faster flowing water has less time to lose heat to the pipe allowing for hot water to reach the user faster. However this matters to a lesser degree because water pressure and flow is only comfortable within a certain range. Anything more and it stings and anything less feels weak.
It all has to do with the type of boiler. Some boilers heat water a lot quicker than others. In my old house when we wanted to was the dishes we needed to put the heater on about an hour and a half before hand. Now we get hot water instantly.
Not sure where you are but in the UK this mainly comes down to the type of heating system.
Larger houses or older places usually will have a basic boiler and a storage tank that stores hot water. The tank is a big copper cylinder about 5ft tall covered in insulation usually in a cupboard somewhere. It often also has an electronic immersion heater that keeps the water hot if it’s not used and starts to cool. In this case the time to get hot water is pretty much just how long it takes for the water in the tank to reach the tap you are using.
Most modern builds, especially your basic <4 bed “mass produced” house will have a combi boiler and no tank. These literally start to heat water when they sense flow in the hot water pipe. With these it can take up to 30 seconds or so to get fairly hot water.
There are of course lots of different designs for generating hot water that have different forms of benefits and issues. The problem of having to run the tap for some time before any hot water gets to it is due to water in the pipes getting cold and having to be drained to let the hot water through. The longer and thicker the lines between the boiler and the tap the longer it takes for this to happen. And the better the insulation on the pipes the longer it takes for the water in the pipes to get cold again.
My shower/tub water gets hot in about 10 seconds, whereas my bathroom sink takes about a minute and a half to get hot. Unless I run my bath at the same time, then my sink water gets hot instantly. I can’t wrap my head around why
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