Saturday, March 10, 2018

My experience with a tankless water heater

The house that I lived in had a 50 gallon storage water heater which was installed when the house was built (around 1995). In 2017, it had put in almost 22 years of service and instead of waiting for it to fail and deal with all the problems that might come with it, I decided to proactively replace it.

One of the options I wanted to investigate was replacing the old water heater with a tankless water heater, which are supposed to be more efficient in their energy usage. What I found was that the price for tank + labor was quite a bit more: $1800 for storage water heater vs $4500 for a tankless (approximately). There are lots of variables in the quotes as it depends on features, permits that you might have to pull and installation location. Its normally cheaper to replace the storage water heater with another storage water heater, as it typically will go into the original location with very little plumbing changes. Whereas, with a tankless water heater, you need to move it to a location where you can mount it (typically a wall) and it needs venting, etc. Apart from the price of a tankless water heater, something else that people complain about is the amount of time it takes to get hot water out of the faucet.

Having looked at my 2 major options, I opted to go with a tankless water, and the main reason was to get more space in my small basement. I dont think the energy savings will justify the price difference (at least in the short run of 5 to 10 years), but I think the extra space I get when I finish my basement will definitely make it worth it.



The above pictures show the old storage water heater and the new tankless water heater and it shows the amount of space I saved by going to a tankless system thats mounted on the wall.

There are many tankless water heater models: Rheem, Navien and Rinnai, just to name a few. I really liked the Navien for its looks, but I settled on the Rinnai RUR98in. RUR98in is a 9.8 gallon per minute (i.e. it can heat by a certain amount 9.8 gallons of water per minute. A RUR80 model would be able to heat by the same amount, 8 gallons of water per minute). Rinnai has a nice tool on their site that can recommend a tankless water heater model for your home: Residential Product Finder. The IN stands for indoor natural gas. The R in the RUR, stands for recirculation and what that means is that this water heater comes with an inbuilt recirculation pump (that Rinnai calls ThermaCirc360 technology).


The ReCirc technology, requires a special bypass valve to be installed at one of your farthest sinks. Once you have the by-pass valve installed, you can set up the water heater to automatically turn on at predetermined times and it will begin circulating water and pre-heating it, so that you dont have to wait for hot-water, which is the biggest complaint that people have with tankless water heaters. In my experience, with the old storage water heater, it used to take about 1 minute until hot water began flowing from the faucet in the mornings (at the sink that was the farthest from the water heater). With the tankless water heater and recirc mode turned off, I find that it now takes about 2 minutes before hot-water flows from the faucet (I have high efficiency faucets, which means 1.5 gallons per minute). Obviously, with the recirc mode turned on, there is no waiting for hot water ( maybe 15 to 20 seconds). One issue I have with the Rinnai RUR98in, is that you get to only control the time at which you turn on the recirc pump in 1 hour increments. This seems inefficent and I wish it was controllable at a finer grain of time (15 minutes or 30 minutes). So, for now, I have the recirc pump turned off as I am trying to figure out the difference in energy consumption between using the Recirc mode and not using it. Something else to note is that Rinnai has multiple ways to turn on the Recirc pump (wifi, sensors, etc). These dont come standard with the tank and have to be bought separately.

Installation Experience

I got estimates from multiple companies. Some were proper plumbing companies, others were local plumbers. The price difference between 2 groups was on average about $750 (local plumber being cheaper). With both groups, I requested that the work be done with all the proper permits being pulled. I choose to use a local plumber, not only because they were slightly cheaper, but because I wanted to support somebody that was local and they came with good recommendations from the community. I bought the water heater personally from Lowes, as I was able to put it on my credit card, which worked out well for me. This option didnt turn out so well for me, as the plumber was very busy and the entire process from when I bought the tank to when it got installed almost took 4 months. So your mileage might vary. Something I would advice on is that, which ever option you pick, you must ask for a permit to be pulled. The main reason for this is, this is a gas appliance and you want all the safety measures to be taken during installation. Again, this is where my experience was not the best: if you look closely at my tankless water installation, there is no valve on the gas in-line to the tank, this is required for safety reasons and a building inspector would not pass the permit until this is installed. Another piece, that I think is missing is an expansion tank that should be put on the water-in line. Now, I need to find a different plumber who can remediate these issues and finish up the permit process. But apart from those 2 issues (that I know of), the local plumber did a good job of installation and everything is nice and clean and is still working 3 months since it went online.

I also, installed a Explosive Gas and Carbon Monoxide Alarm in the basement, just to be sure that there were no leaks, etc (amazon link).

I will continue to post here any future updates I have with my experience with my tankless water heater.ha

Update: 9/8/2018:

The plumber that I had used, did not install a gas shut off valve at the tankless heater. This was a safety issue for me. I had Hot Water Now come out and install a gas valve. At the same time, I had them also perform a flush of the unit. The cost was $150 + parts. Definitely gives me peace of mind and the next time, I can perform the flush myself, as the unit now has the gas shut off valve.

Also, now that I have had the unit running for almost 8 months I have some energy usage stats:


The unit was installed in December and the graph above shows the energy usage and temperature over that period. The winter months, show a higher natural gas usage and I think that is because of the lower temperatures. What is interesting is the energy savings over the spring and summer months, as those are the months, where the only gas consumption was by the water heater and the furnace was off for that entire period (red box). As you can see from the table below, the savings are quite dramatic:


Though the $ amount saved was about $40 for the entire period (Jan to Aug).

Here are some extremely useful videos regarding Tankless water heaters:


Tankless water heaters should last a long time (20+ years as opposed to 10 years for modern storage water heaters). But there is maintenance that one needs to do. Approximately every year or 2, you need to perform a flush to descale the inside. Here is a video that shows you how this is done: