Water Heater layout help for a housing addition (long house)

I know it's extremely hard to describe a layout over the internet so I'll do my best to make it clear. I am starting to call some local plumbers and have them come out and give me some opinions and quotes, but I wanted to see what you guys say first.

Our original house was 1400 sq ft and 60' long. We added an additional 1300 sq ft to the house and an additional 30' to the length. The old house has 1 3/4 bathrooms, the kitchen, and dishwasher. The new addition has the laundry room and the master suite with a dual head shower and large Jacuzzi tub. There is a basement under the entire house, which is where everything will reside.

Current setup:
Standing in the basement facing the back wall I have a Takagi TK-2 about 20' in from the end. One bathroom is directly above it, kitchen slightly to the left, and the other bathroom slightly to the right. The new laundry room is about 40' down with the master bathroom another 20' past that.

Obviously I have a couple problems. The first of which is the delay of how long it takes hot water to reach the new addition. Most of the time the washing machine is done filling before any warm water ever reaches it. When showering we turn on our sink faucets and wait for the hot water before we turn on the shower (as to help reduce the cold water wasted). We have enough time to get our clothes, go to the bathroom, etc. It's killing me how much water and propane we are wasting waiting for the water to hit that end of the house.

I'm unsure how I want to handle this. I've thought about having the Takagi moved to the new addition, and install a smaller tank version at the old location. I've also considered adding a tank at the new addition and leave the TK-2 alone but I have no flue vents in the addition. I would have to either have one installed or install a power vent hwt.

Some things to consider:
- No vent at the addition end
- Large Jacuzzi tub in the addition
- Dual shower heads in the addition
- Would like a fail-over system in case one has issues
- Would like the ability to trickle hot water (don't have that now)
- Don't care about "endless" water in the old section. It allows my teenage daughter the ability to take too long showers.
- Propane fuel
- Size really doesn't matter as it's in the basement
- Forced air heat, no current boiler

Please do not turn this into a tank vs tankless discussion. I'm not leaning one way or the other, I just want something that works.

Thanks
Jared

I would add a small tank, minimal heating element next to the tankless and recirc the hot water off of that.

Similar discussion here: https://terrylove.com/forums/showthread.php?t=18335

Does your house use forced air or a boiler to heat with? If a boiler, had you considered an indirect WH?

Some tankless systems can be set up with a small storage tank and recirculation. A tank type can as well. What some people do is install a small electric WH near the use point and feed it with the remote WH. It provides hot water until the remote source can come up . If you size it properly, you may not notice the temperature dilution caused by the cold water in the line filling the small tank.

With potentially a high hot water use, a single tankless may not provide the volume you need. Some are designed to work together with multiple units to increase the throughput.

You need to either recirculate or move the source closer to the end use points. Many of the recirculation systems can be set up as demand types, and only run when you hit a switch. this would then cause the pump to run until hot was at the sensor (in theory, at your point of use). this would stop all waste water use when calling for hot IF you can wait. If not, then you're back to where you were - recirculate or move the heat source.

jadnashua said:

Does your house use forced air or a boiler to heat with? If a boiler, had you considered an indirect WH?

Some tankless systems can be set up with a small storage tank and recirculation. A tank type can as well. What some people do is install a small electric WH near the use point and feed it with the remote WH. It provides hot water until the remote source can come up . If you size it properly, you may not notice the temperature dilution caused by the cold water in the line filling the small tank.

With potentially a high hot water use, a single tankless may not provide the volume you need. Some are designed to work together with multiple units to increase the throughput.

You need to either recirculate or move the source closer to the end use points. Many of the recirculation systems can be set up as demand types, and only run when you hit a switch. this would then cause the pump to run until hot was at the sensor (in theory, at your point of use). this would stop all waste water use when calling for hot IF you can wait. If not, then you're back to where you were - recirculate or move the heat source.

Click to expand...

Sorry, I should have put that in my original thread as I see it discussed a lot. It would be nice if I had a boiler, I like the layout that you guys have discussed here. I have forced air heat though.

Believe it or not, the TK-2 has been able to keep up with everything we throw at it. My wife and I can be taking a shower in our dual and my daughter can be showering in hers and we have plenty of hot water. Capacity doesn't appear to be a current issue.

It is sounding as if a recirculate may be the final solution. Moving the heat source closer will only take it further away from the other hot water uses. That's why I was considering a second unit. I knew moving my only current heater just moves the problem.

Thanks guys!