Electric tankless hot water heater ?

Question

We are in the process of building a new home and it is time to pick out the hot water heaters. There is so much information out there and I need some help choosing the right one! Here are some details...

We live on Gulf Coast in MS (so it's warm almost all year)

master bedroom - 2 sinks, 125 gal whirlpool tub, separate shower

2 other bathrooms with tub and shower, 1 double sink, 1 single sink

1 additional bathroom with double sink, stand up shower only

Kitchen - sink, dishwasher (cant think of anything else that would need hotwater ??)

Laundry roomm - Washing Machine (a larger one - we are a family of 6)

We do not want gas at all in the house so it must be electric, but I was wondering how the solar/electric tankless units work too, and with all of the bathrooms and appliances using so much hot water how many units would we need to purchase.

Thanks so much! I cant wait to get some insight! This is a very important decision that must be made soon!

Answer 1

The electric tankless water heaters will not supply you with enough hot water. If even half your fixtures were running at the same time you would use about 10 gallons a minute( most faucets put out 1.5- 2.5 gallons a minute) most elec. tankless heaters will do enough for about 1 faucet at a time maybe. A gas tankless will do up to around 7.5-9.5 gpm ,depending on the incoming water temp. Gas and elec both generate according to incoming water temp. If you are looking to go all electric look at a marathon tank type water heater,the have a plastic tank that will not rust out ,yu can get them upto 105 gallons, you will be alot happier with this product.

Answer 2

i've been researching them for an upcoming project,everything i have read and researched has been good,i am looking at them for replacements for tank water heaters in apartments(multi family) what i have found is for alot of use such as what you will be doing,having a 15 gallon reserve will be the move for you.

   by the time you use the reserve,the other will be more than enough to do what you need.

i think there's nothing better than hot water on demand.you don't have the excess to worry about,no tank to have to place and no up keep for that tank.i'm a big advocate for it as you might tell.  

Answer 3

You don't need to use gas for heating water! Note that most dishwashers and washing machines have only a cold water inlet and they heat the water by themselves.

If the climate is sunny (as it is here in Israel) a solar heater works well for most of the year except for the 4 winter months. It is a passive unit without pumps but is a bit ugly and is on the roof. Different sizes and numbers of solar collectors and insulated tanks are available and for a family of 5 who are modest in their showering needs I suggest the tank should be of 180 liter size and two solar panels of about 3 x 6 foot each are necessary. They must face approximately south!

I am not sure what you mean by a tankless solar heater. Here there is no such animal!

Our solar tank also contains an electrical immersion heater for use in the winter, which I regard as wasteful because it takes a while to heat up or it looses heat when running continuously. Instead we have in the two bathrooms an "instant" electrical device also manufactured here, but available in the US. Its performance is not fantastic when the incoming water is very cold, but if you run the water slowly it is effective. Be very carefull about installing this powerful electrical device in the bathroom so that condensation cannot allow water to collect inside or on the internal connections etc. When in use always TURN OFF THE WATER BEFORE CHANGING THE HEATING RATE, or you will blow a fuse. There are at least two models to choose from and it should be planned before the house piping is put in so that it can be used to heat all the bathroom water and not just the shower water (for this an ïn-line"model is needed). For shower water alone, the older kind is suitable. The same applies to the kitchen.

Answer 4

I do not think they have caught on very well. Not sure why. We just built a new house (in Indiana) and neither the architect nor the custom home builder recommended them.

With all your needs for hot water, you would need several tankless units, so I bet it would be significantly more expensive than one large elec water heater.

If you are worried about how fast hot water arrives at a given location, you can put an inexpensive return pump for those locations that are further away from the water heater. These are simple, all it does is keep hot water circulating from the tank to the faucet and back so there is always hot water at the faucet.

Just curious - why don't you want natural gas? It is WAY less expensive than elec. If for safety reasons, gas is just as safe as elec.

Answer 5

I would have to suggest a good quality standard water heater, and gas is the least expensive, and safest choice. The demand tank less heaters are very expensive to purchase, and install. One service call for repairs to one of these will ruin any savings you would have achieved. These are not simple machines. Sometimes less is better. Standard water heaters have proved themselves for years, and the tank less are just not ready for quality service.