LESLIE: Nancy in Pennsylvania is on the line and having a hot-water issue. Tell us what’s going on.
NANCY: Well, my hot water takes so long to – or my water takes so long to get hot when I turn on the spigot. And washing the dishes by hand makes that – I waste a lot of water that way.
LESLIE: Nancy, is this a new problem or has this always been the situation?
NANCY: No, it’s an old problem.
TOM: Yeah. And it has to do with the physical distance between the faucet and the water heater. The farther they are apart, the longer you have to wait for the water to heat up.
Now, newer water heaters today, and especially the tankless water heaters, are very small. And so the way a lot of builders are addressing this is they’re putting in multiple water heaters closer to the bathing or the washing areas of the house. So, typically, you’d have one for the kitchen and maybe the laundry area and you’d have another one for bathrooms. Because these water heaters are so small and so efficient, they can literally squeeze into anything that’s smaller than a closet.
In your case, though, it’s just a matter of the distance that the water has to travel. Unfortunately, in a house like this, though, I would say that it’s unlikely you will save enough money in water costs to make the installation of an additional water heater worthwhile, Nancy.
NANCY: But is there anything else I can do? Like I have been told, different times, that insulating the pipes wouldn’t help or some people say it would.
TOM: Well, the only thing that insulating the pipes will do is it’ll keep the water that’s in the pipes, once it gets there, warmer longer. But again, it’s a distance thing. You turn the faucet on, the water starts to move from the water heater, where it’s hot, to the faucet. And it has to purge all of that cold water along the way. Once it purges, it’ll stay hot but it just takes a certain amount of time for that amount of water – that amount of volume of water – to move through the pipes.
Does that make sense, Nancy?
NANCY: Yeah, it does. And so there’s basically nothing I can do except different water …
TOM: Well, except moving a water heater closer to the – to you. I mean there are recirculators that sort of take water and recirculate it back all the time. But again, that costs energy, too, and that costs plumbing expense, too. And I just don’t think you’re going to save enough to make it worthwhile.
Nancy, thanks so much for calling us at 888-MONEY-PIT.
My hot water heater is just in the garage which is on the other side of my bathroom wall and it still takes over 3 minutes to get hot water to the bathroom ! This is a new house. My old house gave me hot water within 30 seconds anywhere in the house. It was built in the 80’s. Both have pipes in the slab. What’s wrong with this new house. The builder says it’s working fine.
First the builder has used plastic pipes and sized the main pipe at 3/4 inch to reduce pressure loss in the junctions. Second the plumbing was done in a single large loop that starts at the hot water tank and runs around the whole house. The fixtures near the end of the loop will wait a very long time for hot water to arrive through the long big pipe. This method of plumbing is very common today and results in your problem of very slow hot water and yes many builders seem to consider slow hot water “normal” today.
In the past when copper pipe was used it was almost always 1/2″ pipe size used as copper junctions do not cause much pressure loss. 1/2 copper pipe holds far less water that 3/4″ plastic pipe and so the hot water always arrived quickly. Also the copper pipe its self was expensive and so plumbers would plan pipe runs to be as short as possible to save cost insuring hot water would arrive quickly. Long loops of large pipe was not common at all in older copper builds.
Today the better way to plumb hot water with plastic pipe is to use a star topology with 1/2″ pipe running to each cluster of fixtures. A manifold is placed at the hot water tank to connect the many 1/2 pipes, one to each fixture. Some call this the “home run” method. This method results a fast hot water to all fixtures and no pressure drop with two or more fixture in use at the same time.
Why the plumbing code allows the long loops of large sized plastic pipe is mystery to me as it results in large wasting of energy and water as well as the slow hot water problem that drives people nuts.