The Colonial Home Guide to Heat Pumps

At long last, our design notes on the most common type of single family home in Laminar Collective, and quote possibly in all of Massachusetts.

A Guide by Laminar Collective. We want to thank the Barr Foundation, via. Building Electrification Accelerator, and our members for making a lot of this possible! And Ace as well.

This is it. This covers like, 50% of the homes that sign up for LC.

We all know it. We all love it. This boxy, distinctly New England home design is perhaps the most common single family home architecture in the state.

Every single HVAC contractor has probably done an installation in one of these.

Today, we are going to show you exactly how it’s done, and how much it costs.

The Summary

A single family colonial is probably the most sought-after home for HVAC contractors in the state, because from a design and installation standpoint, it’s one of the easiest to work with.

The most common installation setup we see is a mixed system, with a ducted air handler conditioning the 2nd floor bedrooms, and mini-splits covering the 1st floor (& occasionally basement).

Here are the easy parts:

• Typically, a BIG unfinished attic space with standing room. You can run ducts.

• Super standardized layouts - bedrooms on top, open living room & kitchen on 1st.

• Plenty of space around the house to mount condensers & do work.

• Typically will have flat walls on the side, which makes it easy to run line set.

• Located in suburbs, so less traffic to worry about, and easy parking.

Here are the hard parts:

• A fair amount will already have pre-existing ductwork, which means that you’ll have to assess whether a heat pump is compatible with that ductwork.

• Finished attic & basement (but mostly finished attic) will add to difficulty.

• New ductwork is easier to design, but nonetheless, still more difficult to install than mini-splits.

A lot easier to install ductwork if you have a ton of standing room!

Single family homes typically are bigger than units in a triple decker, so the overall job is bigger and contractors love that.

Standard Layouts

These homes typically have a big attic, 2 floors, and a basement:

1. Attic: typically unfinished, sometimes with pre-existing ductwork

2. 2nd Floor: bedrooms, usually 2 or 3, and a bathroom

3. 1st Floor: living room, dining room, kitchen, with a relatively open floor plan

4. Basement: either unfinished, or finished with a utility room for the heating & electrical

Here’s a sample floor plan:

It’s important to note that this attic typically will have easy access from the ground, because only 2 sides are sloped. This is different than the attic in a 2-family home, which are more difficult to access.

Design Considerations

I’m going to first talk about homes without existing ductwork, then homes with existing ductwork.

Why Duct the Rooms Upstairs?

So the primary design decision to make for a home like this is whether you want to install ductwork for the upstairs bedrooms. Let’s lay out the options:

• Ducted upstairs: no wall units, so you get more wall space; also, your bathroom is conditioned. It generally looks nicer, and you get a bit more air mixing because air cycles through the return & gets redistributed through each room.

• Ductless upstairs: each room is an individual zone, so you get better temperature control. Also, you get more space so you can finish your attic if you’d like. However, you’ll need like, a small space heater for the bathroom. It’s also more efficient, since you don’t lose heat in the ductwork in unconditioned space.

Typically, installing ductwork is the more expensive option, but due to the fact that you most likely have an unfinished attic to work with a multiple small bedrooms, it’s about the same here:

With ducting, you generally start off with a high upfront cost (the air handler) and each marginal room you add a duct to is lower cost (since you’re just cutting a hole & attaching a duct). This becomes more advantageous the more rooms you have on the 2nd floor.

For this reason, a lot of contractors will recommended ducting the 2nd floor. Of course, that only makes sense if you’re not planning to finish your attic.

Plans to Finish Attic

We run into a fair amount of cases where people intend to finish the attic at some point, even though it’s not done yet. In these cases, you have 2 options:

1. Installing a ducted system anyway, but either ducts under the floorboard, or in the knee wall space only.

2. Opting for mini-splits (or ceiling cassettes, if you care about the wall space).

One consideration here is that equipment does become more difficult to service in the future if it’s behind the knee wall space, and someone has to crawl to get there. It also makes replacing ductwork a lot more difficult in the future.

Pre-existing Ductwork

For homes with preexisting ductwork in the attic, you’d need to figure out if there are leaks and if the airflow to the 2nd floor bedroom is sufficient to heat & cool the space. Here’s an article we wrote about that:

Ductwork Quality & Performance Testing

Chances are, the smaller your rooms/bigger your existing ductwork, the better. Ductwork that is too narrow for an air handler that needs to push a lot of air to condition huge rooms will make the fan work harder, potentially leading to premature motor burnout.

Exterior Line Runs

Typically, one side of the house will have an unobstructed wall where you can run a refrigerant line straight up to the attic air handler. This makes life a lot easier, vs. homes with Victorian features where you need to find your way around soffits.

Unfinished Basement

If you’re working with Mitsubishi, you’ll need a branch box. Most of the time, this goes into the unfinished portion of the basement. See Installation Process section for more.

Sizing & Equipment Selection

Sizing for the Bedrooms

Consider the typical Manual J heating & cooling load of upstairs bedrooms. They’re typically under 3,000 BTU, with the larger master bedrooms coming in at around 6,000 BTU at most (assuming Mass Save weatherization is done, and you’re not losing a ton of heat through the attic).

These are small spaces. Which means that an air handler would do just fine:

The important thing to note here is that smaller rooms like these open up the possibility of using a medium-static ducted system, like that Daikin FDMQ unit, which take up less space. Good for smaller colonials.

Now, let’s consider mini-splits:

• Mini-split heads, at the minimum, are sized at around 6,000 BTU, with the ability to ramp down significantly lower.

• Having 3 of them would give you 18,000 BTU.

So.. that seems okay as well. So there’s no problem, right?

Sizing for the Entire House

If you have a large house, no, it’s not a problem. But if you have a smaller home (<1,800 BTU) with lower than 22,000 BTU required heating capacity, you may run into oversizing issues.

This is because if you have 3 heads for the bedroom, and 2 downstairs, you’ll need a 5-port outdoor condenser unit, such as this one:

I mean, that, or 2 condensers

The minimum capacity of the R-410a model on this is like, 25,000 BTU. It would render your system oversized. Alternatively, if you go with 2 condensers, it’ll add to the cost.

So.. if you’re thinking about that route, consider other brands with better turndown, or waiting for Mitsubishi’s R-454B models. See update below.

UPDATE: Mitsubishi’s latest R-454b models have much lower minimum capacities, and solves some of these problems!! I write about it here:

Mitsubishi Fixes Its Biggest Mistake

Installation Process

For the sake of simplicity, this describes the install process for a mixed system. If we’re doing an all-ductless system, the steps will be very similar to the installation process for a triple decker ductless system.

It takes about 5 days to install a mixed ducted 2nd floor + ductless 1st floor heat pump system for a standard-sized¹ colonial SFH with no pre-existing ductwork, if you’re working with a crew of 3 people.

Here’s how it’s done.

1. Initial technical walkthrough - typically happens in advance of installation kickoff. This is more important than mini-split installations, because the lead tech needs to decide which ductwork components to bring to the job. Ducted jobs call for a MUCH greater variety of potential components than mini-splits, which are almost always standardized.

   

   Usually, the lead tech will create a list of items needed for this particular design, then bring those things on-site. This also needs to be done to fabricate the plenum & trunk for the air handler. They’ll also confirm, with the homeowner, where the supply registers & return grill should be.

2. Arrival, equipment delivery & cutting registers - once the crew arrives, they bring all the material (including the air handler) up to the attic and start cutting supply registers. They’ll also start prepping ductwork, which involves insulating trunks & branches.

   

3. Mounting indoor units up on wall / drilling exterior holes, incl. basement. - this part is similar to a standard mini-split installation, and can take place concurrently with the ductwork in the attic if there’s another installation tech available. I’ve seen a lot of branch boxes mounted in the basement here.

   

4. Connect line runs and wire air handler & mini-splits - suspend the air handler, if that’s your thing (makes it easier to service). Flare & connect the refrigerant lines to the air handler & mini-split, and to the branch box if you have one (but not the outdoor unit/condenser just yet) and connect the electrical wiring, which you are also running along with the refrigerant lines. Do the same for condensate lines.

   

   

5. Connect ductwork & add line cover - once the supply & return registers are set, connect the main trunk to the branches via. takeoffs, the branches to the supply registers (if not already). Set up an extra condensate drain pan if you’d like. Add line cover to hide the refrigerant & condensate lines.

   

6. Mount condenser - condenser goes on pad, stand, and is level.

   

7. Electrical work - electrical team comes in & makes their way to the panel, and works on the circuit, disconnect, surge protector, grounding, etc.

   

8. Pressure decay + vacuum testing, charging refrigerant - now, the entire system is connected. Run a pressure decay test (ideally for at least an hour, if not half a day/overnight), fix the leaks (mandatory!!), then charge the refrigerant.

   

9. Commissioning & cleanup - turn on the system, and make sure every single subsystem works to satisfaction. Clean up the job site & leave it in good condition.

Do note that these steps don’t always have to take place exactly in this order².

With a relatively small crew of 3:

• The ductwork portion takes about 2 days to complete.

• The mini-split portion takes 1 day to complete.

• Running exterior lines & drilling holes take 1.5 day to complete.

• Charging the outside unit & commissioning the system takes 1 day to complete.

• You’ll want to budget another .5 day in case there are refrigerant leaks.

That’s ~5 (maybe 6) days. Note: we wrote this in the spring, when the weather is nice. This may vary depending on weather conditions (winter = frozen ground & harsh outside, summer = super hot attic).

This is a more complex installation compared to a straight ductless install, so it’s justified that the price is higher. But you’re also conditioning more space, and working with more equipment. So I think that’s fair.

But how fair, exactly, is really fair?

Market Pricing and Cost Breakdown

4/3 update: expect price increases, due to tariffs.

There is a wide range of prices that you’ll find for a colonial SFH installation in the market. There are also significant seasonal price differences. Prices will also be different depending on whether you have existing ductwork or not.

Our spring 2024 single family colonial benchmark. Prices ranged from our negotiated $20,500 deal to nearly $50,000!!

Cost Breakdown - New Ducting + 3 Mini-splits

Consider this cost breakdown for a standard Mitsubishi mixed installation. The equipment & consumables accounts for literally HALF THE COST.

• The overhead at 27% is pretty fair, I think. This includes: office rent, trucks, ordering, logistics, supply chain, warehouse, sales & marketing + customer support³, permit & inspection, funding allocated for service calls⁴ and extra days of work if a job goes over the anticipated timeline.

• For some contractors⁵, the overhead portion is numerically higher + makes up a greater % share of the total, and the overall prices are higher as well to cover that.

What is a Realistic Fair Price?

This is a good baseline price (e.g. during shoulder seasons, not busy summer season⁶):

1. The theoretical minimum for this installation (with Mitsubishi), if you are an experienced HVAC + electrical tech who can DIY this, is ~$16,500.

2. If you pay market-rate labor for a good HVAC friend, you’re at $23,000. Again, zero overhead (or service guarantees, or permit & inspection time, etc.)

3. An indie contractor with really low overhead can probably do ~$28,500, but you’ll have a hard time finding them because they spend no money on marketing⁷

4. A medium-sized, local contractor⁸ may price around $31,000 to $36,000⁹

5. Huge HVAC contractors (e.g. Sila, 128) would probably charge $37,000+ & beyond

#1 and #2 don’t exist for 99% of people, so as a typical consumer, you’re probably dealing with #3, #4, and #5. Unfortunately, unless you spend all your waking hours thinking about the economics & quality of contracting work like we do, you may not be able to find #3 (or feel comfortable vetting them by yourself).

So, for most consumers, you’re dealing with medium-sized contractors & up.

Opportunities for Cost Reduction

• Use another brand that isn’t Mitsubishi (totally fine for <2,000 sq ft homes)

• Avoid the summer!

• Bulk buying equipment.. that said, the problem is that entities that are large enough to do bulk buying (e.g. big contractors) typically have enough pricing power to never pass those savings onto consumers. Laminar Collective, in this sense, is acting like a co-op, but that’s not a super scalable model.

Rebates

Given that most single family colonial homes will require

1. Multiple ports

2. >25,000 BTU in heating capacity (unless your house is like, <1,500 sq ft)

You’ll probably end up with at least a 3-ton condenser. So this is pretty similar to what I wrote in the triple decker guide.

Mass Save offers a $3,000/ton rebate per unit, maxing out at $10,000. Considering the rated capacity of each model, you’d likely receive anywhere between 2.5 x $3,000 = $7,500 to 3 x $3,000 = $9,000 in rebates.

Conclusion

There are 3 important takeaways here:

1. System design & equipment selection is fairly straightforward for a single family colonial home, but sizing matters. Make sure you get a Manual J heat load calc.

2. Installation is actually fairly labor intensive, and consumables & equipment make up about ~$16,000 (!!) if you’re using Mitsubishi.

3. Pricing will likely be ~$30,000+, all things considered, unless you forgo Mitsubishi, join an LC bulk deal, or go with an indie contractor. It goes up from there, since bigger houses may require more consumables.

I’m not gonna lie. When I first started Laminar Collective, I was like

Holy smokes, are people getting ripped off? Installing a heat pump can’t possibly be this expensive!!

In some cases, I think that’s still true. Please don’t pay $50k for a Sila installation; your money is going to ads and Morgan Stanley.

But $30k? Honestly, I get it. We’ll be exploring opportunities to chip away at this number for the rest of the year, but with tariffs and all that - I expect that prices will remain at this level for the foreseeable future.

1. ~2,000 sq ft.

2. For example, you can do the ductless part first, then the ducted. Or the other way around. But you can’t like, do a pressure decay test until all the lines have been connected.

3. See above.

4. Of which there are many during the summer

5. When we organize research installations like this, overhead tends to be lower since we’re not dropping money on traditional sales & advertising. Publishing open research for the public is our marketing :)

Traditional HVAC contractors may be paying salespeople 10% commission, marketing, etc. And the really big HVAC firm that buy the billboards spend a ton of money on marketing.

6. 2 sample adjustments:

• Installing in a summer emergency? Add 5 to 10%.

• How about only 2 mini-splits, not 3? Subtract ~$2,500 to each of these prices.

7. It’s all word of mouth!

8. Or a contractor subsidizing their margins with VC funding in a bid for growth, like Elephant (& some other contractors that take external PE funding)

9. Part of this range is their comfort with ductwork. IF they’re really confident, they may say “okay, no need for a bunch of uncertainty margin - I know I can do this for $32,000”. Otherwise, they may say “in case anything goes wrong, I’m going to tack on an extra $2,000 for uncertainty”.

Compared to the indie contractor, they will have a box truck (instead of a pickup), service warranties, admin staff, etc. They also may have a warehouse!