My hot water on demand system had numerous issues and the house is less than 3 years old. It was one of those European systems too. Weissman ? Viessman? Something like that.

Stick with the traditional hot water boiler.

I went through the hot water tank vs. tankless system when we bought our place in 2025, so take my experience with a grain of salt. For a frame of reference, we have no kids.

We have a dedicated utility room at our place where the hot water tank and furnace live in one space. The hot water tank was a rental unit from an HVAC company (common practice here in Ontario) and it was nearing end-of-life. Because we also needed to replace the furnace and AC unit, we both felt it was time to upgrade based on size, efficiency, and maintenance requirements.

After completing an analysis and comparison of our HVAC requirements and getting about five quotes from various contractors, we decided to go with a Rinnai tankless water system and a Carrier air conditioning unit.

Pros of tankless system: Small footprint and provides enough hot water for our needs. We don't take a bath/shower and do dishes and laundry all at once since we are mindful of consumption. When we hosted my parents, we stress tested the hot water system and it performed well and met everyone's requirements. I appreciate that there is a long warranty for our Rinnai unit and maintenance is simple.

Cons of tankless system: Take a short bit to get hot water. I don't know if newer systems are more efficient or not but it's not a deal breaker for me. When I visit my parents in Vancouver, they have a hot water tank, and it's instant hot water. No waiting or anything like that. There are some models that have an app where you can set a timer for your hot water to be available, but because it's just me and my wife, we don't really mind the short wait, and it's not a big deal for us.

For air conditioning/HVAC, LG was not an option for us, and we had learned of horror stories for long lead times for parts and service. We went with a common, well known brand and model that had plenty of parts and support. Hope that helps!

You want the Asian stuff when it comes to tankless.

Navien or Rinnai are the good stuff.

No, it was leaking and the water from that leak damaged the drywall. After the leak and skylight replacement, I used bleach and painted the surrounding area with mould resistant paint. However, because the mould was in and behind the drywall it kept coming back every autumn.

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That aint a tankless or tanked issue, your parents place probably has a recirc pump that runs 24/7, where as you have "standing" "cold" water between your faucets and tankless boiler

Not that it matters, whats an extra 20 second wait like you said

Most people "want" instant hot water, but they dont realize that comes with the cost of a more expensive system, and higher gas consumption, suddenly they dont "want" instant hot water lol

A plumber family friend went instant on for space savings and money savings, as well as just getting some use case experience for his own business.

He said in an old condo or small townhouse where you own your own hot water system, it's not bad, so it's a similar use case as Asia.

In a big house where you can potentially have multiple hot water consumers, not a good use case unless you go with multiple sources. He has a 3 floor house where the hot water tank was in the basement. Regardless of the system you'd have to wait for the hot water as the water needs to run through 2 floors of pipes before it gets to the top floor. What got him the most was if his tenant was taking a shower and washing dishes, there just wasn't enough flow for example for him to have a satisfying hot shower. It's not cold but just lukewarm. So if you have a big household then you likely wouldn't have a great time or have to stagger uses.


I've seen heatpump furnaces for radiant heat, and heard of dual use systems where one unit replaces both burners for hot water and radiant heating. Not sure how good those systems are though. When we did our renos we just stuffed the biggest tank we can get into the closet as our units were in the basement and we were planning to rent out the basement. We left the radiant heat burner alone since it was still working. The plumber said you aren't going to win by changing out a working system.

D'oh! That's what it is - can't believe I forgot what it's called. Here's a shot of it - since the countertop is white it looks completely seamless:

https://i.imgur.com/jEnUHVg.jpeg

I've been through 3 tankless systems and while I prefer them over a tank it's also been more problematic than any tank system. My current one has already needed a new core just 3 years in and we had all sorts of issues with the gas valve. Our warranty was subsequently voided as they claimed that the installation was not to spec while our previous system had numerous issues with its installation.

Lesson learned: Make sure the installer really knows the system and the requirements behind the installation - don't just take the builder's word for it as my current house was built by a veteran builder (40 years of building homes) and everything else with our house was well done.

I'm pretty sure my tankless system is a Navien and it's awesome. I'd never go back to a regular tank and have to think about running out if we want to do a bunch of things that use hot water close together/at the same time. The footprint being so much smaller meant it could move to a better spot so all but 1 tap in the house get hot water faster than before too, which is a plus.

If you have the need for multiple hot water usage at the same time, you can also install a larger tankless unit. When I installed my Navien, the plumber said the model I had supports up to about 3 hot water taps simultaneously and I could go up. But how realistic is to have continuous 3+ taps running simultaneously? I couldn’t think of a situation in my house.

Dont you run a washing machine 24/6 to launder money?

I have a Navien combi boiler (runs DHW as well as space heating) and have never had an issue with lack of hot water. It is also very efficient and my gas bill per month is quite low.

I also have a Navien in my current house and from my limited research, I saw people also recommending IBC. Anyone have any experience with it?

You can be baller and install both tankless and tank for redundancy.

Also once contractors look up your address they will price their quotes accordingly. Not sure if the construction slowdown right now lowered labour costs.

Wait, you guys wash cloth with hot water?

I wash my cloth with tap cold water. :pokerface:

I have not heard of IBC. But if you decide you go with them, like supafamous said, make sure you find an installer who has experience installing them. I played it safe and went with the Rinnai and even went as far as to asking Rinnai Canada which installer they recommended for install and warranty. They ended up giving me an extra 2 years warranty (total of 12 now.)

IBC is pretty common in the commercial/institutional space. I see them installed all the time.

Did not know that!

The only time I've managed to make the temp from ours drop was while running the washing machine + dishwasher + hand washing dishes + a shower at the same time, and even then it was only a couple degrees.

man all this tankless talk is making me jealous

I am running a 80gal electric hot water tank, electric bill is stupid during winter months.

we have a tankless on each side of the duplex. with 2 separate units each side (top and bottom). Never had any issues with water not being hot at all.
I would say the biggest advantage is the gas bill. with tankless and gas stoves (2 per each side), the FortisBC bill i got is around 50 bucks every month for one side.

Then you’ll be stinky ! You stinky guy ! Need hot water to sanitize

We have a recirc pump and it was honestly the best money i spent when we moved into this house. Previously it was taking up to a full minute to get hot water at the other end of the house… now its like 3-4s

What exactly is this recirc pump and is it exclusively used with instant hot water? If I had to guess, there’s standing cold water in the pipes so there’s a pump that keeps recirculating the water so it’s always hot, hence why it costs more to run? Wouldn’t this put unnecessary wear on the instant hot water?

For context, the house I’m considering will be a 3 story ~4500-5000sqft. Would a single instant hot water be sufficient?

You can install a recirc system with both Tanked and Tankless systems.

You just install a pump and a return line from the hot water supply at your furthest fixture back to the water heater (some units have integrated pumps). The pump just keeps keeps the hot water looping around.

Yes it increases wear an tear on the heater and energy use because it has to keep that loop hot.

However you have control over when you want the recirc system to run. You can put it on a timer, or have it sense when hot water is in use. Some systems are smart and will predict your usage patterns.

'instant' hot water meaning hot water on demand?
i don't think there's anything instant about it compared to a HWT since in both cases the pipes have cold water all the time.