The Tank › Not enough hot water in 3 family house
- June 23, 2016 at 11:26 am #23111jay235Participant
I own a 3 family house where all the hot water is shared from 2×50 Gallons tanks located in the garage. There is no basement. Currently has 12 people living in the 3 units. During winter months, since most of the folks go for work and get ready at the same time, there is not enough hot water.
I called several plumbers to see if the hot water can be separated for each unit where each tenant will get their own 50 gallon tank. But they quoted me a price of $4k since it involves ripping out walls, ceilings etc. They suggested I install another 75 Gallon tank in parallel to the other two and see if that solves the problem.
I wanted to get your insights/views. Do you think this would be sufficient? This would involve purchasing a 75 gallon tank and his labor of $500.
JayJune 23, 2016 at 12:12 pm #23112Larry WeingartenParticipant
Hello: I’d start a project like this by figuring out just what my usage is. Measure flow from every showerhead. At best, they are probably 2.5 gallons per minute. At worst, I’ve found 8 gpm heads! Good heads are made at 1.5 gpm or lower. There is a possibility that just replacing shower heads is all you need. Other things that can be done before replacing or adding heaters are pipe insulation and installing a demand controlled recirc line. Each in their own way reduce the amount of work the heaters need to do. Some very rough math based on ten minute showers and 2.5 gpm heads suggests about 150 gallons per day of hot water used in showering. If you installed 1.5 gpm heads, you’d be at 90 gallons per day. So, do let us know what the existing showerheads are putting out and we’ll see if that’s an area to improve. 😉
Yours, LarryJune 23, 2016 at 1:41 pm #23113jay235Participant
Thanks Larry for responding.
As far as shower heads, I replaced them with a 2gpm last fall. Each unit only has one bath for showering. There is not much to do with insulation since the water heaters are located in a small utility room in the garage and not much piping is exposed.
Is there a way to use the boiler (I have baseboard heat) to heat up the water in the winter and supply heated water to one of the hot water heaters?June 23, 2016 at 2:57 pm #23116Larry WeingartenParticipant
Hello: It’s good to know more about what you have! Sure you can use your boiler for winter preheating. You would plumb in an “indirect tank” to be heated by the boiler. That could feed your existing heaters to give plenty of capacity. I’m no boiler expert, but know where to ask about the details of doing this. Go to http://www.heatinghelp.com and ask this question in “The Wall”. Lots of talented hydronic heating folks spend time there. 😎
Yours, LarryJune 27, 2016 at 6:40 am #23121KULTULZParticipant
As far as insulation goes, he was referring to insulating the hot supply piping which may prove difficult in closed walls. You would insulate just the exposed lines and maybe install mechanical heat traps. The amount of heat loss from non-insulated supply lines is significant.
Also consider a tempering valve(s) which will raise water temp to 140 inside the water heaters but deliver only 120 to the fixtures (to prevent possible scalding/thermal shock.
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