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  1. #1
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    Recommendations for a domestic air-to-air heat pump



    Hello everyone,

    I'm not an HVAC techie and I am looking for help with installing air conditioning in my new house. I'm constantly being discouraged because of claims of humidity and mould problems.

    I'm looking to get a Daikin Ururu Sarara multi split which I hope should help with humidifying (not sure if it works in cooling mode though). I plan to regularly maintain the system. It seems that domestic AC systems are not very common in the UK so it is hard to find good advice.

    The property is a typical 3 bed house (around 70 square meters). I'm planning to install triple glazing and external wall insulation at a later date.

    My questions are:
    1. Can anyone share their experiences with the Ururu Sarara?
    2. How much would the maintenance cost (I'm planning to get either 4 or 5 indoor units)
    3. How can I find a professional maintenance technician who will check everything for me(oil, gas, filters, disinfection and so on).



  2. #2
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    Re: Recommendations for a domestic air-to-air heat pump

    Does anyone have advice for the average home user? I think I will probably get Daikin system but I'm not sure what company to go with. When it comes to credentials, should I look for MCS, HVCA or a Daikin D1 partners?

    Any help would be much appreciated.

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    Re: Recommendations for a domestic air-to-air heat pump

    As you put Japan as your location how are we supposed to help ??

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    Re: Recommendations for a domestic air-to-air heat pump

    just fitted 6 ururu sarara units, only grumble is the indoor units are big and heavy,also the steam hose is bulky and its near impossible to squeeze into inoac 75 trunking.also condensate pumps with sensors-ie blue diamond and other universal pumps the sensors do not always detect cooling and the drip tray overflows, in dehumidify mode the fan runs at low speed to extract the moisture and humidification performance is dependant on the outside conditions,otherwise they work ok,always go for a d1 partner for extra warranty

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    Re: Recommendations for a domestic air-to-air heat pump

    Thanks install monkey. Do you know how much it costs to maintain these systems? I live in the UK, Surrey area.

    If you think that the ururu sarara are ok, what do you consider great

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    Re: Recommendations for a domestic air-to-air heat pump

    why are you concerned about humidity.if your installing triple glazing then damp shouldnt be a problem,daikin do a emura range,top end and look posh.mitsi m series are good,reliable and cheaper than daikin.panasonic units are good and cheaper than daikin.

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    Re: Recommendations for a domestic air-to-air heat pump

    Quote Originally Posted by install monkey View Post
    why are you concerned about humidity.if your installing triple glazing then damp shouldnt be a problem,daikin do a emura range,top end and look posh.mitsi m series are good,reliable and cheaper than daikin.panasonic units are good and cheaper than daikin.
    In all these Japan brands you mentioned, Daikin is the best one for commercial central AC. Maybe this is why semo select Daikin? For domestic heat pumps, it seems that Daikin does not have any apparent superiority. Also we should expand our choices beyond only Japan brands.

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    Re: Recommendations for a domestic air-to-air heat pump

    Quote Originally Posted by install monkey View Post
    why are you concerned about humidity.if your installing triple glazing then damp shouldnt be a problem,daikin do a emura range,top end and look posh.mitsi m series are good,reliable and cheaper than daikin.panasonic units are good and cheaper than daikin.
    In all these Japan brands you mentioned, Daikin is the best one for commercial central AC. Maybe this is why semo select Daikin? For domestic heat pumps, it seems that Daikin does not have any apparent superiority. Also we should expand our choices beyond only Japan brands.

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    Re: Recommendations for a domestic air-to-air heat pump

    Quote Originally Posted by stanleyzhao View Post
    In all these Japan brands you mentioned, Daikin is the best one for commercial central AC. Maybe this is why semo select Daikin? For domestic heat pumps, it seems that Daikin does not have any apparent superiority. Also we should expand our choices beyond only Japan brands.
    I choose Daikin for their ururu sarara which promises to control in door humidity. From what I've been reading, good humidity levels are around 40-50%. Also, I'm only interested in air-to-air heat pumps and in your link it refers to air-to-water systems.

    To answer your question install monkey, I'm lead to believe that humidity control plays a big part in in-door air quality and if I'm investing a lot of money on a heating/cooling system then I might as well get the full solution. Maybe the ururu sarara is just a marketing gimmick. I don't know. I'm open to any suggestions.

    The reason why I wasn't considering mitsubishi is that on some forums people swear by mitsubishi electric while others are adamant that mitsubishi heavy industries makes the best units. All this confusion drove me more towards looking at Sanyo, Daikin, Fujitsu and Toshiba. I get varying opinions on these brands but the overall advice is that they are all good.

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    Re: Recommendations for a domestic air-to-air heat pump

    The overall advice is that all the Japanese units at this level are good. Then it becomes personal preference and specification. Daikin are good, noise levels are low and efficiency is high. But then again so are all the Japanese units at this level.

    MHI whilst pretty good are not top tier. For me that's Daikin Tosh and Mitsi electric.

    As regards indoor air quality if it's such a factor to you then the Daikin is the only way to go. However Unless it is completely air tight then it is possibly an unnecessary addition. I am also concerned that you have mould concerns yet want to add humidity. I would be interested why you have such fears unless you're reading outside the UK. In America and the Caribbean humidity issues can arise if the unit satisfies the cooling demand before real dehumidification occurs. that is why they often slightly under size systems to ensure the unit runs almost continuously which will cool and more importantly dehumidify sufficiently.

    I personally would not be concerned with this as we do not have such humidity problems.

    A mini VRV system would be more than sufficient and personally in the upstairs I would probably a ducted unit in the loft unless individual control is required but most homes really don't need it....

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    Re: Recommendations for a domestic air-to-air heat pump

    Thanks for your reply r.bartlett. I think I wasn't very clear in my first post. Regarding mould, I meant inside the indoor unit where I'm told is a moist environment that promotes mould and so on. This is what I'm being told by naysayers (friends keep telling me to keep to gas boiler central heating and that AC is bad idea).

    I want to add humidity during the winter months when the air might become dry. Maybe I'm mistaken and the humidity will stay between 40-50% in winter when the AC is in heating mode.

    I could also get something other than the ururu and buy some evaporative humidifiers if the air gets uncomfortably dry in the winter. If I do decide to go with Toshiba or ME, what credentials should I ask the installers for (i.e., is there an equivalent to D1 for Toshiba and ME)? Also, what do you think of the air filtration capabilities of the indoor units (plasma vs Daikin's flash streamer titanium apatite filter)?

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    Re: Recommendations for a domestic air-to-air heat pump

    We seem to be getting closer to the centre

    Firstly gas is the most energy efficient way to heat your house. Even the governments own study proved that conclusively and the overall cost of ownership is lower for a std gas boiler (esp now they are all condensing) than any other form of heating. Their only drawback is that they don't provide cooling. That really isn't their fault and it should be seen in the perspective that we only rarely need a/c in the house unless certain circumstances or whatever. The government has set about banning domestic gas boilers (2016) for one reason and one reason only. To reduce the dependence on overseas gas supplies. It has nothing to do with being green or efficiency so don't fall for the I'm helping the environment by buying heat pumps BS

    That aside, the mould and moist environment is another red herring and the units are designed for this and allow for it.

    All a/c systems have condensate and therefore all systems allow for drainage. The problem arises if it's been badly installed or poorly maintained.

    With the humidity in winter warm air systems can dry the air but few feel it's a problem. Personally I believe a wet system gives a nicer 'feel' to the room as when warm air goes off it's immediately cold whereas a boils/rad set up there is still heat available as the rads cool down. You might consider an air heat exchanger system to ensure air changes esp if you're on an insulation/ air tightness trip

    Other manufacturers will offer the 5 years parts warranty no problem but this can be a bit of a double edged sword. I know of one major player in the D1 scheme who massively overprice the maintenance after an install so that entices to look elsewhere and shrug off any warranty if you do. we have one large hotel who took the risk and even with the 2 years less warranty actually paid less over the 5 years. !

    lastly why put Japan if you're in Surrey ?

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    Re: Recommendations for a domestic air-to-air heat pump

    Living in the land of "scorched air" as provided by a gas or oil burner, or electricity, I beseech thee, stick with a wet system however the heat is produced.

    We started this stupid method of heating only because it was cheaper and ducts don't leak water so builders can hire monkeys to install the ducting (apologies to Monkey Spanners and Install Monkey), not because it is better. There is a whole industry in North America with products geared to fixing the problems with air heating....humidification, dust removal from the airstream and balancing air flows. We also have dedicated people who TRY to vacuum out the ducts to get rid of the mounds of dust, junk (and the odd deceased animal) that can be found there.

    Master Bartlett is correct, If you have rads already, stick with a gas boiler. The comfort is much better than any air delivered system.

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    Re: Recommendations for a domestic air-to-air heat pump

    Quote Originally Posted by r.bartlett View Post
    We seem to be getting closer to the centre

    Firstly gas is the most energy efficient way to heat your house. Even the governments own study proved that conclusively and the overall cost of ownership is lower for a std gas boiler (esp now they are all condensing) than any other form of heating. Their only drawback is that they don't provide cooling. That really isn't their fault and it should be seen in the perspective that we only rarely need a/c in the house unless certain circumstances or whatever. The government has set about banning domestic gas boilers (2016) for one reason and one reason only. To reduce the dependence on overseas gas supplies. It has nothing to do with being green or efficiency so don't fall for the I'm helping the environment by buying heat pumps BS

    That aside, the mould and moist environment is another red herring and the units are designed for this and allow for it.

    All a/c systems have condensate and therefore all systems allow for drainage. The problem arises if it's been badly installed or poorly maintained.

    With the humidity in winter warm air systems can dry the air but few feel it's a problem. Personally I believe a wet system gives a nicer 'feel' to the room as when warm air goes off it's immediately cold whereas a boils/rad set up there is still heat available as the rads cool down. You might consider an air heat exchanger system to ensure air changes esp if you're on an insulation/ air tightness trip

    Other manufacturers will offer the 5 years parts warranty no problem but this can be a bit of a double edged sword. I know of one major player in the D1 scheme who massively overprice the maintenance after an install so that entices to look elsewhere and shrug off any warranty if you do. we have one large hotel who took the risk and even with the 2 years less warranty actually paid less over the 5 years. !

    lastly why put Japan if you're in Surrey ?
    Sorry re location, just a force of habit (I sign up to many forums and don't like revealing my id unless I need to) and I can't seem to change it now. Do you mean that gas heating is the most energy efficient or the most cost efficient form of heating? I'm not a tree hugger and not trying to save the world and all that but I don't like fossil fuels (don't like where it comes from, don't like the people that sell it to me, don't like the way it is distributed and I certainly don't like the street level pollution it creates when it comes to petrol/diesel). This is just my opinion and I'm not trying to sway anyone. With the political discussion out of the way, could we please concentrate on domestic heating/cooling systems please

    I understand that I probably won't save any money with an ASHP system and my main interest is comfort throughout the year. I've always believed that air con heating system provides a more confortable and even temperature in a room compared to rads. Is that not the case? How about fan assisted rads with an air-to-water Sanyo ECO CO2 (R744) system. This is a wet system but should provide cooling (not sure if they have fan assisted rads though)

    You say that mould is not a problem if the system is installed correctly. This is my biggest concern... how do I avoid the cowboys!?

    There is a whole industry in North America with products geared to fixing the problems with air heating....humidification, dust removal from the airstream and balancing air flows. We also have dedicated people who TRY to vacuum out the ducts to get rid of the mounds of dust, junk (and the odd deceased animal) that can be found there.
    The ururu sarara is a ductless system... do they suffer from the same problems?

    Master Bartlett is correct, If you have rads already, stick with a gas boiler. The comfort is much better than any air delivered system.
    Again, I'm very surprised to read that. I think that high wall mounted air forced units can't beat under floor heating (in terms of comfort) but thought they were better than standard rads.

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    Re: Recommendations for a domestic air-to-air heat pump

    Any time you have to rely on the rapid movement of air to heat a home, you have to acclimate yourself to abrupt changes in temperature and airflow that any forced air system gives, regardless of type. In a rad system the heat is generally slow moving and almost unnoticeable without putting your hand on the rad (especially ones designed to run at 50-55C). The temp at point A will be similar to that at point B. You won't easily get that with a system that has to move air.

    Heating should always be from the bottom and ideally, AC from the top which reduces temperature stratification (keep a cool head). From a running cost point of view a gas boiler will beat a ductless system especially when run at the above temps. I wish I didn't have to deal with forced air here but most houses built since 1960 are full ducted systems and I have to work with the complaints.

    I'm not against ductless systems (I have a Fujitsu on my 3rd floor for cooling) but they are best for cooling only or on the top floor where some heat comes from below and the stratified air gets mixed. Ductless systems have the same dust problems as full ducted systems in that they are both moving air past a filter and HX and cleaning needs to be frequent. Of course it is not as great an issue but it exists.

    Again, I don't know the house or its air tightness but it is excepted that ducted forced air systems actually increase the heat load of the house by creating air pressure changes around windows and doors. I would believe the ductless system would do the same albeit at a lesser rate.

    As far as mold is concerned, floor heating is the best, then rads. A bit of air movement will keep mold down and this can be achieved by other methods such as an HRV (heat recovery ventilator) and of course getting of the moisture sources . All the "experts' here will try to get a floor heating system with the proper amount of fresh air supply for people with environmental sensitivities or allergies so for indoor air quality it is considered the best.

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    Re: Recommendations for a domestic air-to-air heat pump

    Thanks MikeHolm. So the general advice is that high wall mini splits can not provide comfort throughout the year (heating in winter and cooling in summer).

    It's stange coming to an HVAC forum and reading mostly negative points for HVAC systems and being recommended gas boilers instead

    Am I to understand that the best system is some sort of wet under floor heating or rads with a completely separate system for cooling with high wall mounted indoor units? Or only a single air-to-air mini split with high wall mounted units on the upper floor and fan assisted radiators on the ground floor?

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    Re: Recommendations for a domestic air-to-air heat pump

    Quote Originally Posted by semo View Post
    Thanks MikeHolm. So the general advice is that high wall mini splits can not provide comfort throughout the year (heating in winter and cooling in summer).

    It's strange coming to an HVAC forum and reading mostly negative points for HVAC systems and being recommended gas boilers instead

    Am I to understand that the best system is some sort of wet under floor heating or rads with a completely separate system for cooling with high wall mounted indoor units? Or only a single air-to-air mini split with high wall mounted units on the upper floor and fan assisted radiators on the ground floor?

    That's because we are generally engineers here rather than salesmen...However there is one guy who loves his hp splits (if not LG) so best use the search and chat to him direct

    However if you don't use carpets then underfloor with a low temp hp can provide the 'best of both worlds' but from my own personal perspective I would always fit a high spec combi boiler (not particularly suited to UFH I know) than a high spec HP.

    In all the comparisons done they usually have an old gas boiler then compare it against a new HP c/w high spec insulation and drought exclusion.Then suggest it's no more expensive than the old system. That seems hardly fair..How much cheaper still would it be if the house upgrades were combined with a new top spec condensing boiler??

    Gas boilers are much cheaper to buy and own throughout the expected life cycle. HP's are still overall (climate depending) inefficient and need a breakthrough in technology and price to make them worthwhile. Same as solar etc

    If you have a std 3 bed house in Surrey where gas is already there then logically there is only one choice. Only when you remove logic and insert emotion do HP's make any sense.

    If you want cooling then I would simply add a ducted system to a single vent in each room upstairs and a return at the top of the landing. As a system it's cheaper than individual splits and far less intrusive plus you can incorporate it with a fresh air heat recovery system to maintain indoor air quality if you upgrade the insulation windows etc
    There may be a lack of control but we are only talking about comfort cooling and that sort of system is more than enough for most people...

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    Re: Recommendations for a domestic air-to-air heat pump

    Quote Originally Posted by semo View Post
    Thanks MikeHolm. So the general advice is that high wall mini splits can not provide comfort throughout the year (heating in winter and cooling in summer).

    It's stange coming to an HVAC forum and reading mostly negative points for HVAC systems and being recommended gas boilers instead

    Am I to understand that the best system is some sort of wet under floor heating or rads with a completely separate system for cooling with high wall mounted indoor units? Or only a single air-to-air mini split with high wall mounted units on the upper floor and fan assisted radiators on the ground floor?
    Pure salesmen will sell anything and say almost anything to make money. The person who has your needs at heart will tell the truth as they see it and that is what we, I hope, are doing.

    Mini split HPs are a good solution where traditionally cooling wasn't needed or desired. If you are not prone to big environmental statements in your house then I see nothing wrong with the mini split as a cooling source, but not 2 or 3 or 4 of them as space heating. There are better ways as we have stated.

    Cheers

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    Re: Recommendations for a domestic air-to-air heat pump

    From what I understand is that mini splits are not suitable for heating because of cost and are less comfortable than radiator heating. Is this a fair summary?

    I think I will put this project on hold until the RHI schemes introduces grants for ASHP systems. In the mean time I'll try to visit show rooms or homes that have had an HVAC system installed (any tips where to start from are welcome ).

    On the subject of heat recovery, what do you guys think about the Mitsubishi Lossnay VL 100LI? I'm planning to put one in my bathroom to replace a standard extractor fan.
    http://www.orionairsales.co.uk/mitsu...nger-462-p.asp

    I imagine that the Lossnay would do a better job than the fan or am I horribly mistaken again? Where can I find some to install it for me?

    Thanks for all your help.

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    Re: Recommendations for a domestic air-to-air heat pump

    Quote Originally Posted by semo View Post
    From what I understand is that mini splits are not suitable for heating because of cost and are less comfortable than radiator heating. Is this a fair summary?

    I think I will put this project on hold until the RHI schemes introduces grants for ASHP systems. In the mean time I'll try to visit show rooms or homes that have had an HVAC system installed (any tips where to start from are welcome ).

    On the subject of heat recovery, what do you guys think about the Mitsubishi Lossnay VL 100LI? I'm planning to put one in my bathroom to replace a standard extractor fan.
    http://www.orionairsales.co.uk/mitsu...nger-462-p.asp

    I imagine that the Lossnay would do a better job than the fan or am I horribly mistaken again? Where can I find some to install it for me?

    Thanks for all your help.
    I wouldn't say it was fair or otherwise mearly the view of those who have expressed an opinion.

    That lossnay unit would look bloody horrible on a wall so I would go for a better system which can be mounted in the loft and ducted into various rooms. If you use the Daikin Vams they can have additional HP add on. (not cheap mind)

    Your call...

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    Re: Recommendations for a domestic air-to-air heat pump

    r.bartlett, this sounds interesting if an HP can be retrofitted. I'd like to discuss this further (costs, etc...) if you don't mind. If you are interested, PM me your details and I'll get in touch (don't have enough posts to send PMs). Thanks either way.

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