We are now in possession of our first official estimate for a natural gas based tankless water heater.
Bob from Sears Home Comfort, as described in Part 2, provided us with the quote.
Sears is selling the Rinnai product line of tankless water systems at this time. He recommends the R75SLSi model which, per the brochure he provides, has a capacity of between 4.3 and 7.5 Gallons per Minute depending upon a 70 degree Fahrenheit or 50 degree Fahrenheit Rise, respectively. What is a Rise? And is that enough for our needs?
I have no idea what a ‘Rise’ is and how many gallons per minute a shower uses…..or two at the same time. I think the term ‘rise’ means the number of degrees that the water temperature increases, or rises
, based on the hot water heater. The greater the number of degrees that the hot water tank needs to heat the incoming water, the slower the flow rate (i.e. the slower the water can be processed by the hot water tank. In the winter, the incoming water is pretty cold ‘up north’ so the harder the hot water tank needs to work.
So, could two showers at the same time use more than 4.3 gallons per minute? I don’t think so. But, this is one of the unknowns to use. The brochure we received indicated you can have two showers going at the same time where the incoming water is between 45 and 55 degrees Fahrenheit. I say, for purposes of this discussion that it seems reasonable that this device can meet our needs. But, I’ll need to dig a little deeper on this a bit later if we think we will proceed. Perhaps a ‘home show’ in the near future could be the answer where we can talk to lots of people at the same time.
However, new terms is part of the issue I think with adoption of tankless water heaters in North America. We never really think about it. And we can’t relate to new terms like ‘Rise’ or gallons per minute.
This model comes with a 12 year warranty for the heat exchanger while all other parts are covered for 5 years with labour for 1 year.
However, I could not find a Canadian web site with this particular mode. I could only find the Rinnai U.S. web site. Disappointing. And, this model is said, per the web site, to be new this year. Is it like when buying a new car never, ever buy a new car in it’s first model year? Don’t know.
The price? Bob’s quote is for a few dollars shy of $3,000 all-in, with payment terms of no payment or interest until April 2009 (i.e. 12 months) or no interest and monthly payment of $116 over 24 months.
I like the payment deferral options.
So, this unit seems to meet three out of the 4 of our requirements:
Does it meet the last requirement, i.e. financial payback? Let’s look at the numbers tomorrow.
To continue with the next article in this series, simply select this link to Part 4.


































2 responses so far ↓
1 barry // Sep 18, 2008 at 2:12 am
so how did all this play out? did it meet your needs of flow usage and how was the pay back?? I am considering doing this as well. thanks!
2 Dan // Sep 18, 2008 at 10:37 am
Hi Barry,
Rats. What happened to the link to Part 4? Geesh.
Sorry about that, Barry. The link to Part 4 is now at the end of the article.
In sum, we decided not to go this route for several reasons. In the next few articles we outline the two estimates we received from separate installers and you will see why.
Kind Regards,
Dan
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