Electric Hot Water Heaters - should I install two smaller ones or big one?

Shaun B Published: June 28, 2019, 2:14 p.m.Last updated: July 30, 2019, 4:05 p.m.

I am building a house (super insulated) that has me considering using two smaller water heaters vs. one larger one.  Our house will be slab on grade, with the 4 bedrooms, 2 bathrooms, and laundry on one side of the house in 2 levels, and the kitchen and one full bath at the opposite end of the house on one level.  The water heaters will be electric, perhaps heat pump style.  Should I consider two hot water heaters, one at each end of the house or go with a larger hot water heater and locate it near the bedrooms and just run the hot water to the kitchen/bathroom?  We are on a well/septic if that makes a difference.  Thanks

Shaun, from Uxbridge

Responses (1)

Mike Reynolds
Mike Reynolds July 30, 2019, 3:59 p.m. Reply


Hi Shaun,

If you’ve got that big a house on a slab then we would say yes, it’s a good idea to have two tanks to service individual sides of the house. And it won’t cost a whole lot more to have two smaller tanks rather than one big one. It would certainly cut down on energy loss and wasted water in not having to feed hot water from a long distance.

The upfront cost of heat pump water heaters would be quite a burden, so I wouldn’t do that for both, but maybe for one of them if one side of the house will have the majority of use.

 We would also caution you not to get too enamoured with ‘tankless and on demand water heaters’, they have their place, but when running off well water there is an increased risk of them breaking down if there is high mineral content in the water. I installed one in my own house (it was not cheap) and it only lasted about 3 years until a coil burnt out and I had to switch it out for a standard water heater.

Here are our pages about home water efficiency, choosing low-flow fixtures and toilets, water-efficient showerheads and heat pump water heaters. If you are looking to improve your overall home efficiency and you have the budget to do it, our favourite heat pump water heater is the SANC02 (see here). It is the most efficient, but as you may have guessed it is also the most expensive!