DIY Home Improvement Forum banner
1 - 20 of 20 Posts

·
Registered
Joined
·
38 Posts
Discussion Starter · #1 ·
Looking to add AC to our main living floor. The upstairs has a heat pump with ducts and the basement has a heat pump unit on the wall, nothing for the living floor. Both of those are connected to a single outdoor unit. Due to the type of Windows (crank out) we cannot use a window box unit to sipplement. Which would be more efficient in operation (I know the Heat pump route would be about $800 more for install) :

another heat pump at 12k btu vs stand alone AC 12k btu we can rig to go out the window? Would I ever recoup those install costs if the heat pump is truely more efficient? I also got a quote to move the basement 9k btu to living area for a grand which seemed high but also an option.
 

·
Registered
Joined
·
14,004 Posts
The difference in a ductless split hp vs ac is almost none existent now for some manufacturers. (they add all of the hardware for a hp but never put the electrical to use it for the straight ac models) They are reasonably efficient, and would provide significant improvement to comfort to what your setup sounds like.

How big is the main floor? How many rooms? Is it primarily one large room or many small ones?

Is a ductless split the kind of unit you were getting quotes for?

That price to move the basement one is fairly reasonable. It's possible to do it yourself, but you have to be mechanically inclined and will have to buy some tools.

Personally, I'd go with the HP, and leave everything else alone. You'll appreciate it during the more extreme weather, where the whole house is comfortable, not just one spot.

Cheers!
 

·
Registered
Joined
·
231 Posts
Are you needing more heat or more cold or both??? 2 pc on window??? Can you remove the glass??? Remove the glass with the frame that is around the glass?? Rual King small window unit cool only $99.00 - pics of window?? What area are you in??
 

·
Registered
Joined
·
38 Posts
Discussion Starter · #10 ·
Just looking to add AC but as someone said, the extra heat back up source is nice. Square footage is about 800 and consists of an open kitchen/dining and living room area to cool. Windows are all one piece with a picture attached. The heat pump would look kind of ugly unfortunately I think. The portable unit would just be put in the closet during showing when we go to resell. Considering one of those units that free stand on the floor and the exhaust tubing goes out the window. But if the efficiency is there for the HP then may go that way.
 

·
Registered
Joined
·
15,580 Posts
Considering one of those units that free stand on the floor and the exhaust tubing goes out the window. But if the efficiency is there for the HP then may go that way.
These things are total junk and are known not to perform well, not close to rated capacity. Especially if indoor air is used to cool the condenser coil -> blows out a lot of conditioned air.

Don't know how the space is heated now but if it's with direct electric resistance a heatpump mini-split is a no-brainier.

Unit seems ugly? There are some fancy art-cool models - head hidden, probably very costly.
 

·
Registered
Joined
·
14,004 Posts
There's a bit of a mix-up of terminology. But I think that I understand now.

When you say HP, you mean one of these right? These are actually called ductless or mini splits.
http://www.heatingontario.ca/web/graphic/Ductless-Air-Conditioning-12.jpg

They come on both AC only models and HP models. The portable units also come in AC only and HP models and AC with electric resistance heat. Those portable units also split between 1 and 2 pipe systems. You'll have to specify which you're talking about.

HP means that the refrigeration component is reversible, allowing heat to be moved either from inside to out (AC) or vise versa(heat). It is significantly more efficient then resistance heat. (Like an conventional electric stove)


Portable units:
1) generally much more noisy then any other type of AC.
2) only 1 speed, on and off. So either it's noisy or it's not cooling. They come with a thermostat built in, so it'll cycle on and off as needed.
3) very low efficiency
4) ducting
- duct pipes must run from unit to outside. Usually with the included window brackets. They don't fit all windows. Some people think they are unsightly, but are still necessary.
- single pipe: sucks air from inside and blows it outside during operation. This is required on these units or else they are just dehumidifiers. This means that the already low efficiency is even lower by wasting the nice conditioned air inside and throwing out outside. (At this point, they are barely better then opening a window, while still using power)
- dual pipe: uses 2 pipes connected to the window bracket. These suck suck air from outside instead to operate. These are more efficient then the single pipe but no where near an installed unit. They are still usually less then 8 SEER.
5) Some countries are still allowing for older r22 systems to be imported. They are half the efficiency as r410 models. It's illegal here.
6) You usually can't tell if a unit is an HP model or AC with resistive heat from the box. Resistive heat is quiet but very expensive to run. Unless you live in a very warm climate and only need heat once a year or less, they cost too much to consider.
7) expect less then 5 years from these. They are cheap and disposable. Nothing to fix on them.
8) They are cheap, and easy to setup. Great for backup, but don't expect long life or great performance from them.

Mini split:
1) more expensive, and must be installed. They are more DIY friendly then conventional ducted "central AC."
2) highest efficiency available of all AC types. Usually between 18-22 SEER and some are higher. At the same cooling level as the portable units, they consume 1 half or 1 third the power. (often less)
3) Whisper quiet. Part of that efficiency, is that they have over 100 capacity levels. It's all controlled by the built in thermostat, so it's still just as easy to use. You generally can't hear the difference in speeds inside, and at the lowest level, it's so quiet it's hard to hear. The Outdoor unit is slightly louder, but still incredibly quiet.
4) expect a solid 5-10 years from these. Some last longer, but they don't make things like they used to.
5) Average price, especially for easy installs. Price difference between AC only and HP models are minor if anything at all these days.
6) There are over a dozen types of indoor unit. The wall version is cheapest and easiest to install, making it even cheaper. (time is money after all) You can get in-wall ducted, in ceiling flush mounted, floor models (they look like covered radiators, etc.
http://www.iceageheatingairconditioning.com/images/daikin-air-conditioning.jpg

Central AC: (adding for completeness)
1) needs a central ductwork system, not cheap or DIY friendly to install. (most new houses come with it though)
2) a bit less efficient then mini-splits but not by much. (between 14-22 SEER)
3) only the most expensive models are modulating, otherwise you get 1 or 2 capacities. (high, low off) Cheapest units are only on and off, at 14 SEER. The thermal mass of the house offsets this so most people don't notice.
4) They can be just as quiet as the mini splits, but you get what you pay for here. There are methods and add-ons that make them much more quieter and slightly more efficient.
5) Also comes in HP and AC only models. However HP models are generally more expensive. However these are Significantly more configurable.
6) most expensive option and least DIY friendly. Expect a solid 10 years from them, and good performance as long as its cleaned and maintained. (all types of ACs require some maintenance)


If you found someone to install a new mini split for less then 2 grand, that's a great price. (If you don't plan on DIYing this) The install makes or breaks the whole thing. A bad install will cause nothing but headaches. Do since homework on the installer first, and read some of the posts here on how to install one so you know how he's doing.

Cheers!
 

·
Registered
Joined
·
15,580 Posts
2) a bit less efficient then mini-splits but not by much. (between 14-22 SEER)
I disagree.

The ability to cool only the rooms needed without any duct losses, and variable capacity, allowing for oversizing to quickly pull the temp down without sacrificing dehumidification makes the mini-split at the same seer rating vastly more efficient than central.

With central, even if installed with the ducts in a basement, there are losses because contractors never meticulously seal the ducts. A/c going into a basement is wasted.

Central makes sense when there's existing ductwork for heating or the space to be cooled isn't very open concept.
 

·
Registered
Joined
·
15,580 Posts
Required cooling capacity depending on the space could be anywhere from 1 ton per 500 to 1200 sq ft. So many factors.

9000 BTU may not be out of line for 800 sq ft especially with no attic overhead and no duct loss unless it hits 100f in the summer.

Others may swear high and low that it won't be enough capacity based on "experience", but when you have a proper install, no duct loss and the correct charge you may be surprised at how far a little cooling can go.

Old school "experience" only tells the arrogant experienced ones what worked in the past, not "why" it worked. They only care if the machine works and if they get payed without complaints, not if 1/3rd of the capacity gets lost to an attic or the temp has to be turned down to 68 to kill the humidity. Oversizing can mask problems like leaky ducts, low airflow, improper charge. Thankfully u don't have to worry about the first two with the mini-split.
 

·
Registered
Joined
·
14,004 Posts
Heres what I have in the basement that could be brought upstairs for 1k, it's a 9000 btu. They recommended 12,000 btu for the space and it would be 1350k for that job. This is connecting to my pre existing outdoor unit.
Yup that's a mini split.
How much does it currently run? (both heating and cooling) If it's barely running, then it makes sense to move it. But if you use those spaces every day or so and it runs a fair bit to keep that area comfortable, then don't move it.

These units modulate very well, usually down to at least 20%. So if it's faster for 12,000, it'll be able to run only at 2,400btus. That's about equivalent to 700Watts of power. (my PC can throw off more then double that alone) This is why they work do wonderfully.

Personally I'd go with a new mini split, but ultimately it's up to you and your budget. You'll likely however save more then enough in electricity over it's life to justify the additional price over a window shaker. (or portable unit) I'm assuming that you need it for more then a few weeks a year.

Cheers!
 

·
Registered
Joined
·
14,004 Posts
Required cooling capacity depending on the space could be anywhere from 1 ton per 500 to 1200 sq ft. So many factors.

9000 BTU may not be out of line for 800 sq ft especially with no attic overhead and no duct loss unless it hits 100f in the summer.

Others may swear high and low that it won't be enough capacity based on "experience", but when you have a proper install, no duct loss and the correct charge you may be surprised at how far a little cooling can go.

Old school "experience" only tells the arrogant experienced ones what worked in the past, not "why" it worked. They only care if the machine works and if they get payed without complaints, not if 1/3rd of the capacity gets lost to an attic or the temp has to be turned down to 68 to kill the humidity. Oversizing can mask problems like leaky ducts, low airflow, improper charge. Thankfully u don't have to worry about the first two with the mini-split.
He asked for help, not an industry bashing. A properly sized, setup, and maintained central split can be just as efficient as a ductless split. It achieves Economies of size. Compare apples to apples, as in both having inverter tech, exv, etc and then it falls better in line.

To be honest, it might sound silly, but I like to enjoy every room in my house most of the time. Not just one room at a time while waiting for the next to cool/heat to comfortable levels. But, then maybe I'm a silly, not so old fart.

It's not our faults that you've been burnt by crooks. Get over it and move on already.

Cheers!
 

·
Registered
Joined
·
15,580 Posts
Nothing against split systems, just have to look at the cost-benefit, potential pitfalls.

It's not our faults that you've been burnt by crooks. Get over it and move on already.
I haven't been burned by crooks.

The potential for being burned is there; part of helping is advising on what to ask about/advocate for, not just blindly saying to "trust your contractor". Groups of people protect their own, especially when it's a question of livelihood - just the reality of how people behave.

In this society, you can't trust any professional to do what's best when it comes to decisions which have a long term impact -> Not your contractor, not your doctor, not a lawyer.
 
1 - 20 of 20 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top