Tankless Combi Boiler, Standard Boiler or other system recommendation needed

Big_Finner

Not sure why but an initial thread I started last night just disappeared for some reason. I was able to go back to the original posts and answers but for some reason it is gone from the boards so here it is as I am still in search of a lot of answers.

Hi,

We are currently putting together plans to build a 1 bedroom garage suite with kitchen and 1 bath (dishwasher and stackable laundry as well). I am leaning towards using a combi tankless to run a cooler pex zone in the garage slab and also a comfortable room temperature zone int the suite above the garage. The build has a 25'x21' footprint (just over 500sqft). The hydronic system seems to be the best choice at this point as the suite and garage have to be separated due to monoxide so that would mean a furnace feeding the upstairs suite and one for the garage if I went that way. I live in Edmonton, Alberta, Canada and it gets cold. -40C cold at times which translates to -40F. However the space will be small and I plan to seal and insulate very well.

My problem is I just can't seem to find any reviews anywhere on combi tankless systems. Possibly someone here can point me to some good reviews of these boilers?

I am also open to advice on which combi's people would recommend and which they would advise I stay away from.

BTW I also like the idea of the combi system as it is a compact solution and all the mechanical's for the entire build will be in the garage and I would prefer that I don't end up having to eat up a large portion of my garage with a walled in mechanical room.

Thank you ahead of time for any advice . I am also open to other solutions if anyone see's a good one.

Here were some answers that were posted before it disappeared.

kcopp Member Posts: 2,810
4:57AM
My suggestion.... I'm sure others will chime in w/ their fav. I like this one because there a A LOT fewer parts to break.
The installer is key.
http://ibcboiler.com/ibc-products/dc-series/

Leon82 Member Posts: 344
5:00AM
Since it's only 1 bathroom you can probably use a smaller unit which will help with the small zones

GW Member Posts: 2,601
6:34AM
I’d recommend a smaller boiler with a basic indirect water heater. Combi units have more btu, more cycling

Big_Finner

Thanks so much for all the advice so far. I really appreciate it.

kcopp said:

My suggestion.... I'm sure others will chime in w/ their fav. I like this one because there a A LOT fewer parts to break.
The installer is key.
http://ibcboiler.com/ibc-products/dc-series/

Thanks- You mention a LOT fewer parts to break with this IBC, and from the little bit of customer reviews I have been able to find online it appears like these combi tankless systems might be a very unreliable requiring expensive repairs often. However as I have only been able to find very few reviews I have been wondering if I can trust the few I found.

So do you know if for the most part these combi boilers tend to be problematic and expensive/difficult to repair?

Also do you know who the suppliers of these IBC boilers are, what their reliability is like compared to typical furnaces and if you know of any reviews of them?

You also mention the installer is key. Can you elaborate on why that is the case? As well what should I know overall about boiler systems and their set up so that I can pick an installer wisely?

I am sure it is my ignorance and likely also a touch of arrogance but I have trouble wrapping my head around why and how these systems are difficult to set up and can be so easily set up wrong? I'm not saying I don't believe you, however in my head I can't comprehend how heating water and running it through pex can be that complex?

Leon82 said:

Since it's only 1 bathroom you can probably use a smaller unit which will help with the small zones

Any idea on roughly what size you would think? Keep in mind that possibly one day I may want to close off the garage door and use that space for office or living space. So that would make it a heating requirement of 500 sqft of concrete slab at ground level and 500 sqft of apartment above to heat.

GW said:

I’d recommend a smaller boiler with a basic indirect water heater. Combi units have more btu, more cycling

I am by no means opposed to this as I am fine if the boiler and HWT take a little more space and use a little more energy if it is a better choice than a combi tankless.

I would really like to hear more on why you recommend this route however?

Zman

I agree with GW. The boiler that is big enough for the DHW demand load will be way too big for the heating load.
I like the Triangle Tube Challenger if you go with the combi.

Big_Finner

Thanks so much for all the advice. I really appreciate it.

kcopp Member Posts: 2,810
4:57AM
My suggestion.... I'm sure others will chime in w/ their fav. I like this one because there a A LOT fewer parts to break.
The installer is key.
http://ibcboiler.com/ibc-products/dc-series/

Thanks- You mention a LOT fewer parts to break with this IBC, and from the little bit of customer reviews I have been able to find online it appears like these combi tankless systems might be a very unreliable requiring expensive repairs often. However as I have only been able to find very few reviews I have been wondering if I can trust the few I found.

So do you know if for the most part these combi boilers tend to be problematic and expensive/difficult to repair?

Also do you know who the suppliers of these IBC boilers are, what their reliability is like compared to typical furnaces and if you know of any reviews of them?

You also mention the installer is key. Can you elaborate on why that is the case? As well what should I know overall about boiler systems and their set up so that I can pick an installer wisely?

I am sure it is my ignorance and likely also a touch of arrogance but I have trouble wrapping my head around why and how these systems are difficult to set up and can be so easily set up wrong? I'm not saying I don't believe you, however in my head I can't comprehend how heating water and running it through pex can be that complex?



Leon82 said:
Since it's only 1 bathroom you can probably use a smaller unit which will help with the small zones

Any idea on roughly what size you would think? Keep in mind that possibly one day I may want to close off the garage door and use that space for office or living space. So that would make it a heating requirement of 500 sqft of concrete slab at ground level and 500 sqft of apartment above to heat.



GW Member Posts: 2,601
6:34AM
I’d recommend a smaller boiler with a basic indirect water heater. Combi units have more btu, more cycling

I am by no means opposed to this as I am fine if the boiler and HWT take a little more space and use a little more energy if it is a better choice than a combi tankless.

I would really like to hear more on why you recommend this route however?

Big_Finner

Oh, just to be clear I am simply looking for heating solution for best solution for the space. I am not hell bent on a combi by any means and am open to all options of products that might work. Just trying to find the best solution.

Here would be in order the top things that I believe anyway are my my priorities:

1. Reliability and life length.

2. Something that does not take a ton of space eating up the garage (This was why I am leaning towards radiant as it would only involve a single unit to heat both the garage and the suite. Forced air will mean two furnaces)

3. Price (We are trying to stick to a pretty tight budget but a single radiant boiler system solution that costs more than a typical furnace is okay because the build would require 2 furnaces anyway. I would like the solution to be decently energy efficient but I am fine if it is a little less efficient if it meets requirements 1 and 2.)

Big_Finner

Zman said:

I agree with GW. The boiler that is big enough for the DHW demand load will be way too big for the heating load.
I like the Triangle Tube Challenger if you go with the combi.

Hi, thanks for that. I am completely fine with going with a boiler and hot water tank. Can you provide a few options on boilers you feel would do a good job on this?

Zman

Technically you should perform a heat loss calculation of the spaces and size the boiler based on that. With your ~1,000 square feet, I am sure that you just need to buy the smallest boiler available.
I would suggest the Lochinvar WHN056 with a 30 or 40 gallon indirect. Just pipe it up per manufactures drawings.

Big_Finner

Zman said:

Technically you should perform a heat loss calculation of the spaces and size the boiler based on that. With your ~1,000 square feet, I am sure that you just need to buy the smallest boiler available.
I would suggest the Lochinvar WHN056 with a 30 or 40 gallon indirect. Just pipe it up per manufactures drawings.

So would your recommendation be to steer clear of the combi units then?

When I first started looking into things a week agoI was kind of leaning towards the Navien NCB-E Combi-boilers.

Big_Finner

Thanks so much for all the advice so far. I really appreciate it.

kcopp said:

My suggestion.... I'm sure others will chime in w/ their fav. I like this one because there a A LOT fewer parts to break.
The installer is key.
http://ibcboiler.com/ibc-products/dc-series/

Thanks- You mention a LOT fewer parts to break with this IBC, and from the little bit of customer reviews I have been able to find online it appears like these combi tankless systems might be a very unreliable requiring expensive repairs often. However as I have only been able to find very few reviews I have been wondering if I can trust the few I found.

So do you know if for the most part these combi boilers tend to be problematic and expensive/difficult to repair?

Also do you know who the suppliers of these IBC boilers are, what their reliability is like compared to typical furnaces and if you know of any reviews of them?

You also mention the installer is key. Can you elaborate on why that is the case? As well what should I know overall about boiler systems and their set up so that I can pick an installer wisely?

I am sure it is my ignorance and likely also a touch of arrogance but I have trouble wrapping my head around why and how these systems are difficult to set up and can be so easily set up wrong? I'm not saying I don't believe you, however in my head I can't comprehend how heating water and running it through pex can be that complex?

Leon82 said:

Since it's only 1 bathroom you can probably use a smaller unit which will help with the small zones

Any idea on roughly what size you would think? Keep in mind that possibly one day I may want to close off the garage door and use that space for office or living space. So that would make it a heating requirement of 500 sqft of concrete slab at ground level and 500 sqft of apartment above to heat.

GW said:

I’d recommend a smaller boiler with a basic indirect water heater. Combi units have more btu, more cycling

I am by no means opposed to this as I am fine if the boiler and HWT take a little more space and use a little more energy if it is a better choice than a combi tankless.

I would really like to hear more on why you recommend this route however?

Leon82

To make a decent tankless water temp rise you need higher btu. If you don't have enough baseboard or heating mass to suck out all that heat the boiler will turn on and off alot while heating.
Your heat loss may be 10k. On 40 degree days you don't need much btu output

A smaller boiler with turn down can drop it's firing rate lower than a Combi so it can run longer