HVAC Recommendations

[pixelated]

Firstly, I am not familiar with US terminology used in HVAC discussions such as capacity in tons etc. Simply put, if a central unit breaks down the whole house is affected, it happened with one of our two systems and we decided individual wall (not window) units was the way to go as it took away the risk of the whole house being affected. If your winter is mild they work well and only take a few hours to install and cost pennies to run. BTW I have no idea what a lineset is so please ignore my comments if they don't apply. Minisplits are a relatively new thing in the US from what I can gather and they don't work in temps below zero.

Fujitsu and Mitsubishi, and presumably others make mini splits that provide effective heat down to -15 F/-26 C without using heating elements. Heat pump technology has come a long way.

I went through a bit of a leap of faith when we bought ours, but the claim is real. Residential mini splits are relatively new here, but I see more of them all the time.

 

[Bob D.]

To be clear I'm not pushing the Mr. Cool system, I just came across that in my search as an example of a mini-split.

And I agree the line can be trimmed to length, their manual instructs you to coil up the extra tubing in the manner I stated. That's what I got from reading through the manual. But once you do that (trim the lines) there is no need to buy the pre-charged lineset, just get some ACR tubing and run it normally, evacuate the system, and charge. And once you remove the pre-charged lines which is what makes it a DIY setup you might as well get a regular mini-split, but you'll pay quite a bit more than what their systems go for. Costco sells the Mr. Cool line as do many other retailers, so if anyone is looking at one of these shop around.

 

[Joelm]

Firstly, I am not familiar with US terminology used in HVAC discussions such as capacity in tons etc. Simply put, if a central unit breaks down the whole house is affected, it happened with one of our two systems and we decided individual wall (not window) units was the way to go as it took away the risk of the whole house being affected. If your winter is mild they work well and only take a few hours to install and cost pennies to run. BTW I have no idea what a lineset is so please ignore my comments if they don't apply. Minisplits are a relatively new thing in the US from what I can gather and they don't work in temps below zero.

Fujitsu and Mitsubishi, and presumably others make mini splits that provide effective heat down to -15 F/-26 C without using heating elements. Heat pump technology has come a long way.

I went through a bit of a leap of faith when we bought ours, but the claim is real. Residential mini splits are relatively new here, but I see more of them all the time.

We did the same last year with Mitsubishi Zuba heat pump. The house was noticeably warmer last winter. Even when we hit -40C with the windchill. It is nice not being on natural gas. The only gas in our whole house is for our gas fireplace that we keep for ambiance and in case of power outages.

 

[Peter Kelly]

Firstly, I am not familiar with US terminology used in HVAC discussions such as capacity in tons etc. Simply put, if a central unit breaks down the whole house is affected, it happened with one of our two systems and we decided individual wall (not window) units was the way to go as it took away the risk of the whole house being affected. If your winter is mild they work well and only take a few hours to install and cost pennies to run. BTW I have no idea what a lineset is so please ignore my comments if they don't apply. Minisplits are a relatively new thing in the US from what I can gather and they don't work in temps below zero.

Fujitsu and Mitsubishi, and presumably others make mini splits that provide effective heat down to -15 F/-26 C without using heating elements. Heat pump technology has come a long way.

There actually is a heating element in the pan of the condenser to keep it from icing up when it gets really cold. It's what separates the better units that really can operate in low temps from the cheaper ones that effectively stop working when it gets to the 30F to 40F range.

 

[Coen]

Someone was concerned about having the wall mounted air handler. I tried to explain there are alternatives. I found this which shows the options for multi-zone splits available from one company. Other brands offer similar options. On a multi-zone system you have one condenser that connects to 3 or more air handlers inside. The air handlers can be a mix of types/styles.
https://mrcool.com/wp-content/dox_repo/mc-oly-mz-br-en-01.pdf

If you already have ductwork in place the only advantage this offers is individual room control. You can heat one room and have AC running in the adjacent room. Hard to do that with most home AC or heat pumps.

In commercial installations like office spaces, schools, or hotels it's done all the time. Usually a 3 pipe hot/chilled/common return hydronic system with a mixing valve modulated by a thermostat in each room to control temperature plus a fan speed control.

I don't think most multi-splits allow simultaneous heating and cooling. Afaik it's either one of them in the entire system.

I hadn't considered a mini-split system because I didn't think we had a suitable location to run the lineset or mount the condensing unit.  Plus I'm not sure it would have been allowed by the HOA anyway.

Land of the free, enslaved to the HOA, loololol.  [big grin]

I honestly can't comprehend how a country to allows freedom of speech, freedom to be armed keeps around HOA's that dictate your property.

 

[Coen]

Someone was concerned about having the wall mounted air handler. I tried to explain there are alternatives. I found this which shows the options for multi-zone splits available from one company. Other brands offer similar options. On a multi-zone system you have one condenser that connects to 3 or more air handlers inside. The air handlers can be a mix of types/styles.
https://mrcool.com/wp-content/dox_repo/mc-oly-mz-br-en-01.pdf

The link did not work for me but I just Googled it and found the Mrcool site.  I am interested in this for an additional and to supplement my upstairs which has never been correct.  Anyway, thank you Bob D. for this information.  There is only one retailer in Ohio about 100 miles away but I plan to go talk to him and find out if this will work for me.  I tried to talk to some local contractors about installing what they sell, just have not gotten very far with them.  I understand that, remodeling raises more questions than replacement or new construction, and they would rather I have my checkbook out than my notebook with questions.

I see the lines are 25', 50', 75' and so forth.  I assume you cannot cut the lines since they are charged. So if I only need 30', do I just snake the rest inside a cavity in the wall?

Again, thanks for the info, and I do plan to go visit the one representative in Ohio.

The link works if you paste it in again when you get the error. It's a site that doesn't allow external deeplinking. However, if you come from their error page... it's not external anymore eh.  [tongue]

DIY install of split AC, even the ones with pre-filled lines and vacuumed condensor might be a violation of the law, at least in Europe it is. I would go with a real set with piping cut to size and professional commissioning.

 

[jeh]

It doesn't use the existing line set but it looks no different.

Yes, the interior, wall-mounted half of a split system would be ugly for most areas in the home but as I said there are other styles which are less intrusive.

I believe I have seen mini-splits with ducting that goes in the ceiling to be more like a traditional system. Minisplits throughout a house unless ducted do not complement most decors.

Don't be fooled by the siren's song of a heat pump as a replacement for a gas furnace and AC. If you have gas heat you will not like heat pump heat as it is not even remotely close to being warm. Need to move more than 3 degrees with a heat pump or if the temperature gets below 40 or so, the backup heating coils fire up because the heat pump cannot extract enough heat from the air nor can it do it quickly. The strips are electric coils and will start your electric meter spinning like the second hand on a clock.

A gas furnace has no trouble heating up a house and keeping it hot. If you are insistent on a heat pump consider getting one and using the furnace as the backup heat source. Another option if you want one is to get a geothermal system. The Inflation Reduction Act of 2022 has generous tax credits for geothermal systems. They are expensive, but the Act gives you a 30% tax credit (not a deduction). A bonus is their is no outdoor unit, which works if you have room for it.

 

[Coen]

It doesn't use the existing line set but it looks no different.

Yes, the interior, wall-mounted half of a split system would be ugly for most areas in the home but as I said there are other styles which are less intrusive.

I believe I have seen mini-splits with ducting that goes in the ceiling to be more like a traditional system. Minisplits throughout a house unless ducted do not complement most decors.

Don't be fooled by the siren's song of a heat pump as a replacement for a gas furnace and AC.

Do you even realize AC works in the same way?

If you have gas heat you will not like heat pump heat as it is not even remotely close to being warm.

You won't be able to notice any difference with floor heating. However, if you insist on heating an oversized out-dated home without insulation based on undersized radiators that require 90 degrees C. input to achieve 20 C inside with -10 C outside... your problem is not the heat pump.

Need to move more than 3 degrees with a heat pump or if the temperature gets below 40 or so, the backup heating coils fire up because the heat pump cannot extract enough heat from the air nor can it do it quickly.

Nonsense. It's a matter of getting an installation with the right power. Also user education.

The strips are electric coils and will start your electric meter spinning like the second hand on a clock.

Yes, so you should dimension your installation around never needing the resistive coil.

A gas furnace has no trouble heating up a house and keeping it hot.

It's just as easy to under-dimension a gas burning heating device as it is a heat pump.

If you are insistent on a heat pump consider getting one and using the furnace as the backup heat source.

The whole point about getting a heat pump is you can dump your natural gas connection, saving in fixed cost.

Another option if you want one is to get a geothermal system. The Inflation Reduction Act of 2022 has generous tax credits for geothermal systems. They are expensive, but the Act gives you a 30% tax credit (not a deduction). A bonus is their is no outdoor unit, which works if you have room for it.

Yes but that is a matter of cost up-front vs reduced use-cost. Also very neat to use passive cooling with ground source heat pump systems.

 

[ChuckM]

If you are insistent on a heat pump consider getting one and using the furnace as the backup heat source.

The whole point about getting a heat pump is you can dumb your natural gas connection, saving in fixed cost.

Snip.

In B.C., Vancouver, for example, some people have heat pumps, and they serve houses fine year round. But not in Alberta where temperatures can drop to -30C or lower. These past couple of days we have had -25 C (-40C windchill). No responsible heating companies here will advise a customer to install a heat pump alone without a furnace as a backup. Pipe bursts aren't uncommon in our winter. Our water tanks are commonly gas-heated. So heat pumps work for some, but not necessarily for all.

[attachimg=1]

 

[pixelated]

Our heat pump does fine down to about -5 F, and doesn’t use any resistive heating elements.
It will produce heat down to -15F, but at those temperatures the house loses heat faster than the heat pump can replenish. If the house had better insulation, it would probably keep up.
But we knew and understood it’s limitations going in, so when it’s very cold we augment with wood heat.
Fortunately -15 is rare where the house is situated, and below 0 only happens a few times, most years.
It costs far less to run than our propane furnace did, and keeps the house more comfortable to boot.

 

[ChuckM]

-5F or -15C is about right. Heating specialists here recommend more or less that or temperatures not lower than -20C as the cut-off point for a backup furnace even when houses are fully insulated (R22 (RSI 3.08) or better for all above ground framed walls).

 

[Coen]

If you are insistent on a heat pump consider getting one and using the furnace as the backup heat source.

The whole point about getting a heat pump is you can dumb your natural gas connection, saving in fixed cost.

Snip.

In B.C., Vancouver, for example, some people have heat pumps, and they serve houses fine year round. But not in Alberta where temperatures can drop to -30C or lower. These past couple of days we have had -25 C (-40C windchill). No responsible heating companies here will advise a customer to install a heat pump alone without a furnace as a backup. Pipe bursts aren't uncommon in our winter. Our water tanks are commonly gas-heated. So heat pumps work for some, but not necessarily for all.

[attachimg=1]

In that case you go with the ground source heatpump. The payoff is faster then anyway because of the higher use. You can connect the tank hot tap water to it too. A little bit lower efficiency for the hot tap water due to the higher temperature gap is to be expected, but as it's usually a tiny fraction of total heating that is negligible. If you like to shower a lot or have a bigger household, get a heat exchanger for the shower waste water.

What "heating companies" advise is usually just food for the trash bin. I've talked about the installation branche in NL before; to prevent CO deaths the government now outlawed (well, five times and three years delayed) installing and maintaining gas-burning heating devices unless certified. However, the total amount of CO deaths is "5 to 10" per year and in 95% of cases it's because of recent installation or maintenance done by a certified installer. Soooo... if we assume the 5% of CO deaths is currently caused by faulty DIY installation, the maximum lives saved per year is .25 to 0.50
I'd say even less or negative, because there is no legal requirement to actually have maintenance done.

But the whole circus of bureacrats, schools and educators definitely benefited...

 

[Coen]

-5F or -15C is about right. Heating specialists here recommend more or less that or temperatures not lower than -20C as the cut-off point for a backup furnace even when houses are fully insulated (R22 (RSI 3.08) or better for all above ground framed walls).

-5 F and -15 C aren't the same
-5 F is more like -20.5 C

Fahrenheit; another weird unit that needs to die.

 

[Joelm]

Ottawa hit -32C (before windchill) earlier this month and we were fine with our heat pump.
We installed a Mitsubishi Zuba  a year and a half ago. This is our second winter with it and it has been great. We got rid of the furnace and have electric heaters as backup. In all this time I think the electric heater came on 1 night. And that was just for maybe 30 minutes.

 

[ChuckM]

Ottawa hit -32C (before windchill) earlier this month and we were fine with our heat pump.
We installed a Mitsubishi Zuba  a year and a half ago. This is our second winter with it and it has been great. We got rid of the furnace and have electric heaters as backup. In all this time I think the electric heater came on 1 night. And that was just for maybe 30 minutes.

That's exactly what heating specialists are saying here: don't rely on a heat pump alone, and a backup heat source, be it a furnace, wood stove or electric heater is advised. Below -20C temperatures for days and days in a row are nothing unusual in Manitoba and Alberta. This morning:

[attachimg=1]

 

[woodbutcherbower]

In the UK, we only have H (setting fire to our furniture because the cost of natural gas and electricity are stratospheric) and V (opening a window). It only gets hot enough for us to need AC once every 10-15 years, so on that day, we take off our shirts instead and complain about how hot it is. And we aren't white - we're blue. It takes us a whole week of sunbathing to turn white.

 

[Coen]

In the UK, we only have H (setting fire to our furniture because the cost of natural gas and electricity are stratospheric) and V (opening a window). It only gets hot enough for us to need AC once every 10-15 years, so on that day, we take off our shirts instead and complain about how hot it is. And we aren't white - we're blue. It takes us a whole week of sunbathing to turn white.

red  [tongue]

And then visit Amsterdam, use too much paddos and drown in the canal.  ;D

Was the UK even slower with minimum insulation requirements as NL was?

 

[woodbutcherbower]

Was the UK even slower with minimum insulation requirements as NL was?

Insulation? You mean the 2 vests, 4 shirts, 3 sweaters and 2 coats we all wear 24/7?

 

[ChuckM]

Multi-layers are the key to staying warm in extremely cold conditions. When I need to work in the shop before it's warmed up enough (I.e. it's under 5C or so), or shovel my driveway in -20C weather, I bundle up with three layers of clothing under my winter jacket.

 

[Packard]

I’m no expert, but I’ve read in the past that a 2 stage AC is substantially more efficient and they keep the humidity lower and maintain a more consistent indoor temperature.

In fact, the conclusion I drew from reading about it, is that the 2 stage is superior in all regards except for the cost of the unit.

There is a lot written on the comparisons.  It is probably worth reading.
https://www.google.com/search?q=sin... stage&ie=utf-8&oe=utf-8&client=firefox-b-1-m