Installed Navien NR-210 tankless water heater and 48" Power-Pipe drain heat recovery unit

We want to reduce our natural gas use, reduce our GHG emissions, but very importantly, reduce our long-term energy costs. One of our largest costs was the $28/mo bill for our water heater tank from Reliance. After nearly 8 years in our house we have more then paid for it with no costs incurred by the renter. We had done an energy audit last year through the ecoENERGY Retrofit - Homes program. The provincial government matches the federal rebate grant. This program was cancelled by the federal government and current projects must be completed by March 2011. So, we are finishing just in time!

We decided to install a tankless water heater and to have a drain heat recovery unit to pre-heat the water before the heater. I purchased it from Merlyn Power in Kitchener. The install went smoothly though took the whole day. It is too early for me to make any comments about performance. Some quick observations:

• the drain heat recovery unit significantly heats the water prior to it going to the water heater - measurements to come!
• despite getting a fairly large 210 model, running two bath tubs and a kitchen hot water tap resulted in the tubs running more slowly. This likely won't be a problem with shows due to the low flow shower heads. Also, the water line going to the two tubs is only 1/2"
• when turning on the hot water tap it takes a little longer for the water to become hot. Water from the original hot water tank came out quite hot once it reached the tap. It seems that the tankless takes several seconds to have the exiting water "hot"
• the system takes much less space than the water tank. I can re-arrange this corner of the basement now

We had our system installed yesterday. Then I went off to my runner's boot camp and spoke to superman David Brooks. He had one installed yesterday too, nearly the same model, but he got the 210A model with the small recirculating pump and reservoir. Then, speaking to running commrade Steven, he tells us he has the 210A model installed for the past 3 years.
I want to measure the heating of the water, I'll report here in the coming weeks.

UPDATE: 2012-12-05. After having this tankless water heater in the house for almost 2 years, we are very happy with it. We did have a tiny problem when it didn't seem to work last autumn. I looked around and saw that an error code indicated problems with the air intake. Outside the 4" intake pipe was clear. So I opened the panel and checked the air filter. It was perfectly clean but there was a leaf on the filter! Removed the leaf, easily replaced the filter, and the system has worked perfectly ever since.
One thing I would do differently is to install the 210A model with the recirculating pump. We have to run the water for about 1-2 L once the warm start to become hot. Before the morning face wash i need to run the tap quite a bit for the water to run hot.

UPDATE: 2013-09-30. I notice on the Navien website some of their models have the "ComfortFlow technology". It has a built-in recirculating pump to reduce what it calls the "cold-water sandwich". That would be a nice feature I'd like to have now based on my experience.
A second thing I have been wanting to add to this blog post is for people to consider using their tankless water heater as a home heating system. It can replace your furnace if you have a hot water spacing heating system, including in-floor heating. You'd need a special model with a higher capacity than a regular hot-water heating system. If you need to replace your hot-water system furnace, consider replacing your hot water tank and furnace at the same time with one single hydronic system tankless hot water system.