HVAC Replacement: Ditching an Old Furnace and A/C for Mitsubishi Heat Pump with HyperHeat 

I’m an HVAC guy I learn more here than most channels. Thanks.

Another excellent video. Thank you for showing what retrofitting a less inefficient home is like!

Food for thought: I hope to see more open simulation models/software. Cooperation between manufacturers to design better common standards and tools could help improve models and system design over time (like detecting and reducing overfitting and underfitting in simulation models). It would be a win-win-win for everybody. Great video! Thank you, Corbett.

Switched out a conventional HVAC in a similar climate (Memphis metro and Atlanta Metro have pretty much the same climate) for a heat Pump (different brand) and the comfort level is up and the electric bills are lower despite a significant increase in electricity rates. Mine has a 12 year replacement warranty. In January we went down to 0 degrees for about 3 days at night with highs in the teens and the Heat Pump performed very well.

All single speed ac systems are oversized for almost 90% of the year. The beauty of inverter systems is they ramp up incrementally as the day heats up and use very little electricity to do it. And then as the load is off they only put in enough energy to maintain temp and humidity. Mitsubishi sets the gold standard for how the air handlers are built and insulated. Just be careful to use the correct size refrigerant lines and control wire. It’s worth it hands down.

Fantastic work here, you’ve got me hooked for the next one!

I had the 4 ton version of this Mitsubishi installed last summer in Colorado, no heat strips, plenty of heat at something like -17F. It's a 2005ish house so that helps. I'm not too surprised that it was able to handle 20F. It only seems like magic.

The Hyper Heat Mitsubishi units are fantastic at heating even at 5 degrees. I go off the max capacity from the dimond system builder on a 15 degree day in my location. Most of our customers don't need the electric strip heat unless it's an old home.

Awesome! I'd love to learn more about your parents' home updates. We are in an old brick home and looking to modernize.

Good run down thanks.

I would love to keep my system fan running on high all the time, but it drives me crazy! Just the sound of the wind coming out of the registers is all that I hear. I have the Mitsubishi intell-Heat duel fuel system here in south central Wisconsin and I don’t know when the last time my natural gas furnace ran. Through the entire Winter so far it’s been the heat pump. It did get pricey one month that we had a week and a half of sub-zero weather but it kept 2000+ sqft. Home at temperature.

Rated + Maximum Capacity is handy to see as it gives you another data point to compare output, COP etc. In reality it won’t apply to a specific application unless that output and temperature correlates directly, but it’s still nice to have for the nerds out there. 😊

I'm about to have this exact model and size air handler and outdoor unit installed at my home in a month. It's replacing 20 year old AC and natural gas furnace, both single stage. All ducts are inside the conditioned space with an Aprilaire E100 dehumidifier. 1979 2 story slab home, 2000 sqft, with insulation and air sealing being improved as I make my way through projects. I'm really interested in the part about keeping the air handler fan speed set to high, assuming the correct static pressure setting. I was surprised to hear the Mitsubishi rep recommend the high speed as opposed to variable speed as well. I thought the variable speed blower motor was going to be one of the highlights of the system, working in tandem with the variable speed inverter compressor. What's the story with that? I'd love to hear more about the reasoning on that. The correlation between compressor speed and blower motor speed was about the only thing I wasn't sure about how it worked, but figured I'd find out once equipment is installed. Been researching this equipment and reading manuals for 2 years now, haha.

I wonder what the cost of operation is vs a gas furnace at the same temp

Excellent video. Thank you.

so many questions coming up in my brain, I religiously keep track on my gas consumption in an Excel file. Can I use it to estimate/dimension my heating load for the new heat pump? Absolutely love this channel... pondering to become a Pat. supporter...

Great video, i used the same filter assembly i like it so far. Curious what kinda total static the system done with the new unit?

Hey Corbin, when you mentioned the A/C size and I glanced at the house, saw the old 4-burner furnace ... I had a feeling 60K BTU was oversized. Often what happens is companies do not suffer a business penalty in sizing that way for 2 reasons: There's no humidity issue with oversizing heat as there can be with cooling that short-cycles, and also because they never want to hear customers complain it takes too long to warm the house no matter how cold it gets outside or how infrequently super cold temps might happen. Bingo: *We're a nation of oversized furnaces*. I'd forgotten about that data logger. A modern smart thermostat can do something similar. Neither will exactly equal a Manual J ... but for an existing system they don't really need to, right? Log how often the system runs for a given time period. That tells you the percentage of capacity used for a given set point, to get closer to true capacity needed, even if it means it runs more continuously (which as we know ain't a bad idea.) Say someone had a 60K BTU furnace but learned it only runs 1/3 of the time. 1/3 of 60 = 19800 BTUs (but now, re-do the math to add more BTUs because most gas furnaces are only putting out 80-95% of that 60K INPUT number ... look at the yellow EPA sticker) Take BTUs and divide by 12 = tonnage of heat pump needed. 2 tons. MAYBE 2.5 tons. It's not exact nor does it need to be. The homeowner just needs to not freak out that it runs longer or takes longer to warm a super cold house. It's no sin to plug in a cheap space heater once a year and run it for an hour! :)

Just had my first winter with a Mitsubishi SVZ upstairs, and now I’m debating between S and P series to replace my final furnace. Thanks for the side note on orphaning the water heater - how do you test if that’s a concern? We want a heat pump water heater but ours is less than a year old due to an emergency replacement

Here's my question for the Mitsubishi heat pumps: can you specify an evaporator temperature and then control some forum of modulating reheat, e.g., hot gas, electric, hot water etc.? Stand-alone whole-house dehumidifiers are nice, but I would much prefer an AHU that I can just program to give me air at a certain dew point and reheat temperature, 45F dew point and 55F dry bulb, for example. Variable air volume for zoning would be nice, too. If you already have a variable-speed compressor and fan, I don't see any reason it shouldn't come as a standard feature.

On homes where I get to do a load calculation, or new equipment install, I try to also install some type of monitoring device. I prefer Ecobee thermostats but use Emporia Vue energy monitors as well. When you start comparing run times, to load calcs, you really start to see how huge the gap is between Manual J and the run times on design days, especially in the heating side. I would say I’m averagely seeing 70% oversized in heating mode. It can be a bit frustrating that Man J is our “standard” when there’s so much discrepancy. I get there have to be some “safety nets” but it seems quite excessive. The reality is that using run times for sizing make electrifications much more possible compared to places where we are only allowed to use Man J.

Great stuff as always! If the Manual J is so far off, is there a general modifier than should be applied to the calculations for a new high performance build? Or is it very specific to the houae deaign?

Corbett, I have been looking at building my first house and want to go with a heat pump, but I live in Northern Michigan in climate zone 6. Heat pumps aren't particularly common in my area with most people using propane or natural gas furnaces, and many still burning wood for heat. This makes it difficult to find a company with much experience in installing heat pumps. I would love to do a geothermal heat pump system, but they are about 2-3 times the cost of an air source heat pump and natural gas furnace hybrid system that is recommended by some of the local HVAC companies I have talked to ($30k to $40k installed, but could be much more depending on what kind of ground loop they need to do). I would like to get away from burning fuel for heat if possible and am wondering if an air source system like the one in the video would work for me, or would I be using the heat strips so much that a geothermal system would be worth the extra upfront cost? Typical winter temperatures in my area range from 20°F to 40°F, but it is not uncommon to reach single digit temperatures at night with temperatures occasionally going into the negatives. Do you know of any air source heat pump systems rated for use in climate zone 6? Sorry for the lengthy question, and thank you for making these insightful videos, as I have been learning a lot.

waiting until my two 10 years furnace die to do the same. Why you did not jammed an ERV(s) on the returns? Please go soft I am a beginner 😅

The return plenum is tiny compared to what the company I work for installs

Manual J requirements are a disgrace especially for older properties that have been mostly renovated with all new windows and added insulation / sealing of electrical boxes and lights . The entire industry around it isn’t helping either. May as well go square feet method .

When I ask my hvac guy in Nashville about switching to Mitsubishi……he says no way , they can’t get parts when they need them? Is this true or he out of touch

3:30 They don’t recognize the asbestos tape on the duct work??

Bubble wrap is better than insulation?😅