Call in a plumbing contractor.
For an optimal installation, include a drain water heat recovery system in original building plans. Install a coiled copper pipe around the drainpipe. Cool water from the mains runs through the coiled pipe and is preheated on its way to the water heater.
Compliance with standards CSA B55.1 and B55.2, and heat recovery rate of at least 42%.
Where to buy
Drain water heat recovery systems are offered by plumbing contractors.