If you’re interested in installing a SANCO2 combi system in your home and schedule a complimentary consultation, Small Planet Supply Sales Engineer Peter Reppe is the person who will be providing you guidance via the phone. A recent interview with Peter shed some light about his experience with these consultations and what potential SANCO2 combi customers can know about the process.

As the person who does the most customer consultations, including SANCO2 combi consultations, what is your estimate of the percentage of customers who call that can use a combi system for their home?

At least half to three quarters of the customers who have signed up for the combi system consultation are able to install a combi system.  It turns out when we look at the heating loads and so on, most are good candidates.    

What are the factors that you believe contribute to that high number?
One of the biggest factors is probably that the majority of those interested customers are into high efficiency and not just getting off gas heating, but also using a heat pump that doesn’t have the high global warming impact refrigerant.  That’s number one.  Number two is also that often those potential clients have someone on the team other than themselves, such as a passive house planner, that’s able to do the heat load calculations which always forms the basis for us to determine whether a SANCO2 combi will work.  There is a little bit more sophistication on the team when we get started.

Have you developed any rules of thumb that a customer or builder can use besides the heat load that might help them better understand whether they’re able to use the SANCO2 combi?

I would like to refer you to our website, to the little writeup that we have about the BTUs and so on.  That’s condensed on what I can tell you.  If we have a low-temperature heating system, such as radiant floor or radiant panels, and return water temperature of about 90 degrees and no warmer than that, then we can serve 10,000 BTU per hour of heating load in a house.  That’s not just a rule of thumb, that’s the actual limit. 

So, there’s no tricks.  It’s just doing the math?   

Yes, because there’s just some cases where the house isn’t as super well insulated as passive houses, but the heating load is still low because they have enough solar heat gain or lots of internal heat gains from equipment and so on. So, it’s just like doing the numbers and figuring out what the actual heating demand is. Ideally, the most promising candidates are always the ones that say, “I’m going for Passive House” and then we know the heating demand is very low.

When a customer finds out they’re unable to use the SANCO2 because their heat load is too high, or for some other reason, are there other system recommendations you make for them?

Step Number Two is always to find out If attaching a second heat pump would meet the heating load, which sometimes it does.  If that is too expensive for the customer, then I suggest they put in a small electric in-line resistance heater to boost the performance just a little bit. It’s something that’s contained in our standard piping diagrams that ECO2 supplied. 

In some cases, we’re able to find that the client was interested in having air conditioning in their place anyway, which drives them toward a small ductless heat pump and that by itself brings additional heating capacity so we’re splitting the heating load between the SANCO2 combi and another heat pump and that works.  It comes down to, “can we meet the heating load with our SANCO2 heat pump? and if we can’t, then maybe another heat source that we can count on for the heating of the place.  But we’re still happy to show that the 83-gallon tank gives them all the hot water that they need. 

If you were to give a potential SANCO2 combi customer a piece of advice about using a SANCO 2 for a combi project, what would it be?

Call Small Planet Supply to help with selection of the system.  We have the basic design conditions such as maximum heating demand and minimum domestic hot water consumption per day and temperatures of the heating system that we couldn’t get around.  Those are the issues that we would talk through on the phone or by email. 

Customers should be aware that the SANCO2 combi is a highly efficient system that is based on extracting some space heating energy from the domestic hot water tank, so it takes some fine-tuning.  It’s highly efficient but it’s fine tuned in its design and operation.  Nobody should assume it’s like an old, super-powerful cheap gas heater that is just oversized and delivers you whatever you need anytime at whatever environmental cost.

So, would you say that something along the line that, they just need to be aware of how it operates a lot differently than a boiler and customer can’t use that same logic?

Definitely. The whole idea that I want to get across to customers is that we have this important inter-dependency between domestic hot water heating and space heating that keeps the system balanced and stabilized. It something where we need to talk through and look at the actual project and how many people live in it and so on.

What advice would you give a customer in preparing for their SANCO2 combi consultation?

Be prepared to answer the questions we ask in the online sign-up form, which is number of occupants in the house, and if there are any heat load calculations available already, to bring them along. Be prepared to have a half hour or 45 minutes to talk through things because we get into a lot of detail and talk through everything they’re interested in, so it’s not a quick five-minute phone call and “yeah, it’s all good, buy it”.  It's a little bit like a doctor-patient back and forth.  Sometimes I must ask customer personal questions to be able to determine the occupant’s hot water needs.  Is it just two adults?  Or two kids that will be turning into teenagers in five years?  All these things that impact the load on the system and that takes some time to talk through.  It’s a very Informal conversation, not a serious interview. 

Does it make a difference if someone wants a big soaker tub or something like that?

Yes, for sure.  That’s a good example of the type of demand on the SANCO2 system where we need to look very carefully. Because the SANCO2 system can handle lots of water being drained out of the system at any one time, dumped into a tub, no problem.  But it doesn’t want to handle recirculating and rewarming a jacuzzi.  So, it’s just looking into what specifically the customer is wanting in their home. 

It really is a way of understanding the specific way someone is planning to live in their home. And for me to explain to them that the system is in part so efficient because it likes the stratification of cold water on the bottom and hot water on the top.  If that is disturbed by whatever unique system a customer has in mind then, it’s probably not going to work.  It’s always taking a close look at what people want to do. 

On a separate note, I do get a lot of calls where somebody’s trying to squeeze the last little bit of BTUs out of the system by tweaking some unique features in the house and I’ll have to spend an hour with them just to understand what they have in mind. And then to understand that maybe that’s not doable or they should just give it a try but can’t count on the warranty.  They can tinker, that’s fine.

What kind of tinkering are they doing?

Somebody might want to have another draw of hot heat from the tank through some other emitter like fan coil through the garage and preheat the garage a little bit. Or they are thinking of preheating with solar hot water panels.    Some good stuff that I appreciate where they might want to have the heat pump controlled so that it only operates through the warmest hours of the day when it’s the most efficient.  So, to figure can you put a timer on the unit?   Utility companies have time-of-use rate, can we stop it from running from those high-rate times?  Not many clients ask about that, but it does come up.

Are there any unusual projects featuring a SANCO2 combi that you can recall, and if so, what were they?

I do recall some conversations with somebody who wanted to reuse some large stainless-steel tanks in the house and to see if that’s doable with our heat pump.  In general, there is nothing much out of the ordinary that I recall, at least not being aware that they were implemented and built.   

When customers project’s heat load is higher than SANCO2 can adequately heat, have any of them worked to reduce the heat load so they can use the SANCO2 comb?  If they did so, can you remember what specific things they tried to do?

I have had some clients that after doing the heat load calculation , I might have noticed that the wall insulation isn’t that much above code, and they would say, “Okay, I’ll talk to my architect, maybe we can add a little bit more continuous insulation on the outside”  So there were some projects with design changes just to beef up the insulation because they realized it was cheaper to add a little bit more insulation and be able to use the SANCO2 combi. In some cases, they couldn’t reduce the heat load, but they realized that they had so much PV panels on the roof that if we had an electrical resistance back up heater that added a little bit of the heating load that wouldn’t harm them too much, they would get free power. 

In some cases when the heating load is a little bit bigger and I find out that if you only added 1 KW electric resistance heater after the tank to top off the water isn’t delivering enough then occasionally the system is running on electric resistance, just a little bit. That added power consumption as opposed to a heat pump, that’s being delivered by a huge PV system that they might have on the roof.  There are some clients that have so much PV that they’re not worried about the electrical consumption from a little bit of electric resistance. 

In some cases when the heating demand is too large or something else isn’t quite working, I slide into talking about Spacepak because it doesn’t have the interdependency between heating and domestic hot water as the SANCO2 and can handle a higher load and also provide air conditioning.

As the person who does the most consultations, what do you find most interesting about doing them?

I love that I get to talk to everybody, from very focused, serious engineer types that are designing a bigger project to the homeowner who’s just pondering, “would this system work in my old house that I’m planning on remodeling.”   Just the diversity of potential clients.  And having the opportunity to find technical solutions that overlap – what I’m learning from one project or one client some cool tricks that I can use somewhere else.  And, that we have pretty good technical documentation that I know what I’m trying to explain to them, how it works.  And after having done it for two years now it seems with so many cycles of background research with ECO2’s help I feel like I have such a good grip on the whole system. I can walk somebody through it blindfolded.

When did you first hear about SANCO2 heat pumps?

I personally heard about it for the first time back in 2010 when Tad Everhart did his (SANCO2 combi) project in Portland and my firm was recruited to help with the design of the system. That was the first time I heard about it.  This was with the Generation 2, or maybe even the Generation one.  That might have been the first SANCO2 that came to North America.

Since that first SANCO2 heat pumps have evolved, which makes it is easy to feel confident using them and recommending them.  If customers are concerned, about noise, I can say, “no problem”, when they ask about freeze protection, also “no problem” and are far as annual maintenance there’s almost nothing to do. 

Interested in Knowing if a SANCO2 Combi System Can Meet Your Hot Water and Space Heating Needs?

More information about SANCO2 combi systems is available at Small Planet Supply’s SANCO2 for Combi Systems page. You can also self-schedule a SANCO2 Combi Consultations by using the button below.