I'm clueless about heat pumps

Forums › Home Workshop DIY › I'm clueless about heat pumps

teamsteve

59 posts

Master Geek

#143453 15-Apr-2014 13:24

I'm looking to buy + install a heap pump in the next month or so and because I know almost nothing about them, I have a few questions :)

What brands generally have the best quietness / power efficiency?

Is a heat pump a waste of time if my roof insulation is a bit crappy and needs replacing?

I'm looking at getting it installed on the second story of my house - will this add much to the installation cost?

Can anyone recommend an installer in West Auckland?

Thanks!

1 | 2

18118 posts

Uber Geek

ID Verified

Trusted

Subscriber

#1025577 15-Apr-2014 13:38

What heating is in the home now? if there is reticulated gas it would be more cost effective to install fluid gas heaters. Before installing you should first insulate this will reduce your energy usage.

TrendMicro

Best TrendMicro deals for antivirus and malware protection(affiliate link).

teamsteve

59 posts

Master Geek

#1025582 15-Apr-2014 13:43

We have no heating at the moment (unless a non working fireplace counts) , we just used a plug in heater last winter

Dynamic

3574 posts

Uber Geek

ID Verified

Trusted

Lifetime subscriber

#1025583 15-Apr-2014 13:44

Regarding installation, we had a cold call from these guys last year http://smartenergysolutions.co.nz/page/insulation_installation and they ended up doing the insulation underfloor and in the roof. Gov't paid for 1/3, and the other 2/3rds is being paid off over 5 years on the rates bill at a low interest rate. Made it a no-brainer for us and the process and paperwork was easy. I went under the house to have a look and was very happy with the professionalism of the job. I suggest having a cruise around their web site.

Your home will always leak heat (read: money). Heat Pumps slow the rate at which you are feeding money into the house. Insulation slows the rate at which the money leaks out.

“Don't believe anything you read on the net. Except this. Well, including this, I suppose.” Douglas Adams

Referral links to services I use, really like, and may be rewarded if you sign up:
PocketSmith for budgeting and personal finance management. A great Kiwi company.

timmmay

19622 posts

Uber Geek

Trusted

Lifetime subscriber

#1025584 15-Apr-2014 13:45

Read up on them on Wikipedia and such. I have a Fujitsu (2 years old) and a Daikin (5 years old)

CoP (coefficient of performance) specifies their efficiency at a given temperature. I think mine's 4 (4 units of heat per unit of power), but smaller heat pumps are generally high efficiency than larger units. I have a 9kw Fuj Nocria in my living/sleeping area, and a 7kw in my open plan kitchen. If I purchased now I'd get a single larger unit and duct it to each room - it's difficult to move the heat around the house unless it's open plan. It's ok, just not perfect. Also consider you want bedrooms cooler than a lounge, usually.

The outdoor units are very quiet, you often have to get close to tell if they're on. The indoor units vary HEAPS. The Fujitsu Nocria (aircon backwards) on ultra quiet is still about as loud as the Daikin on low/medium, but the Fujitsu is more efficient.

There's little point getting a heat pump if you have poor insulation. The house will be warm, but the heat pump will run constantly and use a heap of power. With good insulation, if you keep your house the same temperature it'll be cheaper, but most people spend about the same (or more) and have a warmer house. I have loose fill wool then two layers of pink batts in my 100 or so year old house, along with foam in the walls and underfloor. If it's 6 degrees outside at night and 20 degrees inside at 10pm, if I turn things off it's 17-18 degrees at 6am. New houses would be a lot better, my house is pretty old.

Don't have the outdoor unit attached to the house, they vibrate and are noisy. Have it on the ground. Get multiple quotes, and do consider ducted, it'd be worth it, especially combined with a ventilation system. A standard heat pump will be $3000 - $5000 if it's on the ground floor, ducted $10K - $20K I guess. It will cost a bit more to run the pipes up a two storey building, or from where you want the outdoor unit, but it's possible - don't let them tell you otherwise. Efficient probably goes down a little.

I can't help with the installer, not in Auckland. There's a lot of coyboys around though, check their reviews on nocowboys.co.nz. Check the warranty too, and their maintenance prices - they should ideally be serviced annually.

MikeB4

18118 posts

Uber Geek

ID Verified

Trusted

Subscriber

#1025585 15-Apr-2014 13:47

teamsteve: We have no heating at the moment (unless a non working fireplace counts) , we just used a plug in heater last winter

Plug in heaters are very expensive. If its a log burner then that is better if its an old open fire then hopeless. It sounds like a heat pump is best but again insulate before you install or it will cost a fortune to run. As for noise, Mitsubishi units are very quiet.

timmmay

19622 posts

Uber Geek

Trusted

Lifetime subscriber

#1025588 15-Apr-2014 13:54

Chimneys let out HEAPS of warm air. The best thing I did for my insulation was to remove the freestanding fireplace as air came in around it from the roof cavity, and plugging a built in one would be huge too. Heat rises, taking your heat out, cold gets in, etc. If you plug one make sure it's insulated.

A heat pump will cost less to run for a given amount of heating, but most people will just turn it up and let it run, costing more. Insulation is relatively cheap, $1-2K for pink batts for most houses I guess. If you run a heat pump in an insulated house in winter you could easily spend an extra $2K. Insulation will have a payback period of 1-3 years I guess, maybe less depending on your habits.

kingjj

1728 posts

Uber Geek

ID Verified

Trusted

#1025601 15-Apr-2014 14:20

Second the Mitsubishi units being quiet. We recently replaced our Blue Seal (long non-existent brand now) with a Mitsi MSZ-GE50VA (5.8kw) and barely notice it now when its on quiet or low-medium. While we have roof insulation, we have no under floor insulation, no wall insulation (external walls are concrete brick) and old single wooden window frames and windows (no double glazing). We also have it installed in open plan lounge/kitchen/dining with hallways and bedrooms. Set to 21 degrees and on low fan setting the room is comfortably warm within 20 minutes normally.

My recommendation is go for Toshiba or Mitsubishi and buy a larger size than your area requires. Mitisbushi's have a good reputation for being quiet. We got our heat pump purchased and installed for about $2400 (with a decent discount). Ducted heat systems are great if you want to outlay that sort of money. Getting a heat pump installed on second story will increase your install costs quite a bit (either for longer pipe length or for getting it affixed to side of house/roof). Good luck.

timmmay

19622 posts

Uber Geek

Trusted

Lifetime subscriber

#1025605 15-Apr-2014 14:36

I chose Fujitsu for efficiency, there was some reason I didn't like Mitsubishi, they do something a bit different around defrosting that reduces the efficiency from memory. They're a good brand though. They do a lossnay ventilation system that can integrate with some of their heat pumps, so you get fresh warm air and efficiency too - it preheats the cold fresh air with the outgoing stale warm air.

5.8kw isn't very large, but a lot more powerful than a 2.4kw fan heater, and a lot more efficient too. The larger the heat pump the lower the theoretical efficiency at full power, but they run at full power much less often so end up more efficient in practice.

LesF

176 posts

Master Geek

#1025622 15-Apr-2014 15:07

We put in a ventilation system at the start of summer, no heating option with it but we will probably add on a heat transfer unit soon. The system was from SmartVent and we were happy with their products and pricing (we reviewed a number of suppliers and products).

It was installed by Harbour Heat Pumps, who cover west Akl, and we were happy with their work. I am happy to recommend them, the guys were good to talk to in that they provided useful information and comparisons of options, without feeling like they were just selling a specific product. Other companies had sent us reps who only knew how to sell the one product and we almost couldn't make them leave.

Sideface

8435 posts

Uber Geek

Trusted

Lifetime subscriber

#1025701 15-Apr-2014 17:00

We have two heat pumps in our rambling old (insulated) house - a Mitsubishi and a Fujitsu.
Both work very well, but the Mitsubishi is quieter - I have to look for the "on" light to tell that it's running.
We also have a Drivaire home ventilation system, which is very quiet (and a lot cheaper to run than the heat pumps).

Sideface

timmmay

19622 posts

Uber Geek

Trusted

Lifetime subscriber

#1025721 15-Apr-2014 17:28

Ventilation systems get rid of moisture, which helps the heat pump work more effectively. It's easier to heat a dry gas (air) than water rich wet air.

There's a huge variation in the ventilation systems available, heat recovery systems are generally best and most efficient. The big brands that spend heaps on marketing are often the least effective and most expensive.

teamsteve

59 posts

Master Geek

#1025814 15-Apr-2014 20:54

Awesome, thanks everyone

I'm definitely going to look into getting our insulation sorted - have just contacted that company about getting an assessment, and plugging this chimney that we don't use sounds like a great idea too

If the option to pay for insulation on top of our rates is still an option we should be able to afford that and a heat pump so hopefully it'll be a very warm winter in the teamsteve household :)

Yogi02

238 posts

Master Geek

#1025844 15-Apr-2014 21:29

Obviously the installation will be more expensive on an upper level.
You can look at mounting the outdoor unit to the outside wall to reduce distance to compressor. - Can have increased vibration/noise.
The distance and access to switchboard is also a variable as new cabling will likely need to be run.

Make sure you get an inverter split system(most are) and pick one that will do an area about twice the area you need to heat/cool. While the purchase price will be higher your average running cost should be a bit lower and it will heat/cool quicker if you need it too.
I have always stuck to either Mitsubishi/Fujitsu and not had a problem

ObidiahSlope

260 posts

Ultimate Geek

#1025874 15-Apr-2014 22:55

HOMER SIMPSON: "We obey the laws of thermodynamics in this house."

As others have posted insulation is important for economic heating.

The usefulness of heat pumps is dependent on the difference in temperature outside and the temperature you want inside as well as the density of the air.

I am located in the south of the South Island. I have a heat pump and on cold clear dry winter nights my pump is really struggling.

In my locale if you have access to firewood and no clean air restrictions I would recommend a wood burner.

Obsequious hypocrite

mattwnz

19374 posts

Uber Geek

#1025886 15-Apr-2014 23:44

What do people think about Hitachi as a brand of heat pump. Had a family member who was quoted a hitachi install.. They also have the choice of a mitsubishi, one of the silver designer series ones, but the sales person said that the exterior cases on the hitachi have special paint that lasts longer.

1 | 2