In the winter, the temperature of the water entering your hot water heater is lower than in the summer. So it takes longer for your hot water heater to heat the water, and it runs out faster. During the summer, the temperature of the water is higher, so it can heat more water in less time, and it does not run out.
I Own A Hair Salon, My Electric Hot Water Heater Runs Out Of Hot Water Very Quickly In The Winter, Yet In The Summer The Hot Water Seems Endless. What Could Be Causing The Problem?
I would suggest that your water heater isn't powerful enough. You want one that is around 7kw-10kw. If you have a 3.5 kw, that's not going to do the job in the coldest weather.
In the winter its so cold that it takes your average heater make it hot enough for but though the motor might be cold so it might be trying to make you warm and itself and although that might be the first thing wrong with it but the second reason is probably that it is over heating itself just try to put on low but not that low low enough too keep you warm.
Your options for water heaters are 29 gallons, 30 gallons, 40 gallons, 50 gallons, 75 gallons, 80 gallons, 100 gallons.
Make sure your thermostat is turned on High. For gas water heater, when turning up view to see if there is an increase in the fire that lights up.
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Upgrade to a larger size WH. But if your tank is already large (75 gal - 100 gal) then purchase a smaller size (30 gal - 50 gal) and have it daisey-chained in conjunction to your current water heater.
I have this problem in my home with running out of hot water in the shower quicker in the winter then in the summer. I found out that after the heat kicks on and its been on for some time there is less hot water. So my best guess is that for the heat it uses the hot water heater to warm the rooms so that's why you run out of hot water quickly. In the summer you don't use the heaters so that's why you have plenty of hot water.