slenzen
Basic Member
Posts:434
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| 21 Jun 2013 03:50 PM |
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Need your help evaluating options.
I have a 3 level walkout town home in MN (zip 55372) top level is loft master bed/bath. Approx sq footage is 3000 sq ft
Unit is prob 25 yrs old w/ original AC and heat, double pane windows, many facing west, standard 2x4 /fiberglass insulation, basement walkout level does have closed cell spray and is finished.
My First option:
is replacing the AC unit and heater, I'm guessing $6-7,000? The AC line runs about 20-25ft in finished sheetrock truss ceiling.
Can AC lines like this be reused that old? Or can new ones be snaked through/pulled through by the old one? Or am I lookin at taking off the sheetrock expense as well?
for heater, I have a vertical stack now, a tech said horiz is better for newer more efficient heaters, but I may have a problem getting the exhaust out to an open air outside wall, w/ sheetrocked ceiling, possible ducting etcc in the truss ceiling. My townhomes are staggered back a bit from neighbor so there is some outside sidewall but it is across a 16ft finished room. Options toward walkout wall are limited because it is underneath the main level deck.
My second option:
What about mini splits for my setup?
they may be cleaner install, help w/ sep zones, but not sure of the cost?
lower walkout level is home theater, pool table, bar, bedroom, bath, utility and laundry room. Cooler in summer and winter.
main level is entrance, kitchen, living, dining, office/bedroom, bath.
upper is loft master bed/bath, much warmer in summer, tougher to cool, easier to heat in winter being loft top level.
could I be better off going mini split for the cost and zoning rather than replacing the old units? how do I evaluate these for the best option?
thanks for your input!
signed,
hot muggy MN in June. |
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slenzen
Basic Member
Posts:434
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| 21 Jun 2013 03:50 PM |
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tried to put paragraphs in but it got collapsed, sorry for harder reading.
tech said old AC unit was 2.5 ton. |
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slenzen
Basic Member
Posts:434
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| 21 Jun 2013 03:59 PM |
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oh and can the mini split setups handle the heating duties for a MN winter in possible below zero cold temps? |
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docjenser
Veteran Member
Posts:1400
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| 22 Jun 2013 12:38 AM |
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so how can geothermal guys be of assistance? |
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| www.buffalogeothermalheating.com |
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jonr
Senior Member
Posts:5341
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| 22 Jun 2013 01:42 PM |
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You probably need to get some local quotes, including some for increasing insulation and air sealing.
A nice thing about mini-splits is that you can add just one to an existing system and make use of its greater efficiency without having to worry about handling the entire load and all areas. |
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joe.ami
Veteran Member
Posts:4377
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| 24 Jun 2013 09:12 AM |
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Posted By docjenser on 22 Jun 2013 12:38 AM
so how can geothermal guys be of assistance?
Yes it sure is too bad there is no ASHP forum. |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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holodinsky
New Member
Posts:1
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| 29 Jul 2013 07:00 PM |
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Yes I would like to see a dedicated mini split forum as it is one of the newest forms of heating as well as cooling highly insulated homes ...regards,Bob
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jokin
Basic Member
Posts:105
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| 30 Jul 2013 07:38 AM |
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I gug this out again for the occasion.... :)
------------------------------------
I followed this geo forum ever since I stumbled onto it via a google search in 2007?, anyway I've learned 99% of what I know about geo from the geo forum guys like joe, engineer, Dana1, waterpirate, docjenser, a10.... and some many others. Recently I helped someone design a heating system for a small relatively tight house. Owner didn't have a basement and saw that due to the layout the ductwork was going to be expensive/ugly... this pushed me in the direction of minisplits. I ended up with (2) single head Mitsubishi Hyperheat units (small 1 ton models), it was a huge stretch for me, to advise someone to rely on an airsource heat pump in a heating dominated climate... but I knew the specs from commercial side experience and had some limited info from this geo forum, I also searched high and low online for more information but found little to none... except for some very light weight articles written by journalists who had no technical background but were only were impressed with something that air conditioned the outside during the winter to provide heating inside. I was looking all over to find information on how others were placing the units, how they ran the units, what success they were having (or failures), how they were making sure there was air circulation, how they were handling OA/ventilation, etc. I couldn't find anything even CLOSE to the wealth of geo specific info at this one forum. There has to be people out there with similar knowledge/experience with ASHP's that are equally willing to share their knowledge and mentor others.... but currently there isn't a place for them to easily exchange ideas (or I would have found it), or for interested parties to easily find the professionals to contact them or just silently learn from them (as I and presumably many others have done so often on this forum). A dedicated ASHP forum at this site could be that place and in the process expose that many more people to the other valuable information at the GB site... from debunking energy efficiency myths to best building practices. I'm not married to geo thermal, just because I have a DIY one heating my house, it was just clearly the best option to keep us comfortable for the lowest cost (life cycle cost) at the time we had to make the decision. Things change over time and for others that rely on my advice or even for myself when I someday need to make a replacement/upgrade/revamp decision, I would love to be able to drawn on a database of substantive ASHP conversation at this site.
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joe.ami
Veteran Member
Posts:4377
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| 30 Jul 2013 09:06 AM |
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We have as you know lobbied for one for some time, but it has illicited no response from the site owners. Perhaps one will pop up elsewhere. |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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Dana1
Senior Member
Posts:6991
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| 30 Jul 2013 02:50 PM |
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Shouldn't that read "...elicited no response..." ? :-)
Answering the now month-old questions...
In addition to the Mitsubishi HyperHeating units (fully rated at -25C/-13F) Fujitsu's recently released AOU-xxRLS2H series are also designed to operate at MN-style outside design temps. Fujitsu's standard xxRLS2 (non-H) series will keep running at low temp too, but don't have some of the cool-temp features (like pan de-icing for the defrost water) that the -H version has, nor do they have a rated output below -20C/-4F, whereas the -H versions are fully rated at -15F.
Whether there's a combination of these that meets your actual heating & cooling loads isn't exactly clear- a Manual-J would be called for, but it's not outside the realm of possibility. A pair of 3/4 ton mini-splits could probably handle your cooling loads for the ~6-7K you're talking about for the 2.5-ton ducted system (assuming you don't have a whole wall of west facing glass and really NEED 2.5 tons) but may be a bit shy on the heating end... or not- it depends on your actual loads. It's likely that you'd need as many as 3 ductless heads, at a total cost of between $6-10K depending on the particulars, but you may also be able to keep it to two with a bit of judiciously placed & sized radiant cove-heaters/panel radiators, etc. If the ductless can handle 85% of your design heating load the cost of supplemental resistance heating could be pretty small-depends on the layout and how you control the auxiliary heating (occupancy sensor in series with T-stat is good). But all good solutions start with realistic load calculations.
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engineer
Veteran Member
Posts:2749
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| 01 Aug 2013 12:14 AM |
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An ongoing multi-week bad experience with repair part availability from an industry leading minisplit brand whose name begins with "M" and ends with "I" (as in "I" have no idea when that control board you ordered 2+ weeks ago will even ship, much less arrive) suggests that if you go with minisplits, particularly in a climate that has the potential to kill (MN) rather than merely inconvenience (FL), redundancy may be Your Best Friend. |
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Curt Kinder <br><br>
The truth is incontrovertible. Malice may attack it, ignorance may deride it, but in the end, there it is - Winston Churchill <br><br><a href="http://www.greenersolutionsair.com">www.greenersolutionsair.com</a>
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joe.ami
Veteran Member
Posts:4377
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| 01 Aug 2013 08:04 AM |
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Hmmm, for some reason my last post didn't take. Curt, in the HVAC business, part shortages and lengthy waits are not uncommon. The fact that everyone has similar weather at the same time suggests that failures may occur in clumps. Things like union strikes or power company problems can cause parts shortages or mass failure as well. Amongst the things you do in this business is have a relationship with your supply house so you can get them to take a board off another unit (quite common). Take them up on that. You also keep a store of space heaters or portable airconditioners depending on your climate for ituations like I had in February where my customer had to wait 10 days for a heat exchanger. Thanks for the spell check Dana  - |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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Dana1
Senior Member
Posts:6991
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| 01 Aug 2013 02:51 PM |
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Posted By joe.ami on 01 Aug 2013 08:04 AM
Hmmm, for some reason my last post didn't take.
Curt, in the HVAC business, part shortages and lengthy waits are not uncommon. The fact that everyone has similar weather at the same time suggests that failures may occur in clumps.
Things like union strikes or power company problems can cause parts shortages or mass failure as well.
Amongst the things you do in this business is have a relationship with your supply house so you can get them to take a board off another unit (quite common). Take them up on that.
You also keep a store of space heaters or portable airconditioners depending on your climate for ituations like I had in February where my customer had to wait 10 days for a heat exchanger.
Thanks for the spell check Dana -
Yer welcome! (I didn't want to leave the impression that there was anything shady going on with being responsive, eh? :-) ) |
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engineer
Veteran Member
Posts:2749
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| 04 Aug 2013 08:53 AM |
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I thought I'd replied earlier to this but maybe my post didn't 'take' either.
At any rate I do have a supply of both space heaters and windowshakers, and they do go out on loan when part or staff availability is a problem.
In this case I particularly despise the drip-drip-drip nature of the promised date of arrival...first it was the end of the week we ordered it, then "Monday for sure", then July 26, then July 30, then "It'll ship July 30". Now it's "we have no idea when it'll ship"
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Curt Kinder <br><br>
The truth is incontrovertible. Malice may attack it, ignorance may deride it, but in the end, there it is - Winston Churchill <br><br><a href="http://www.greenersolutionsair.com">www.greenersolutionsair.com</a>
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slenzen
Basic Member
Posts:434
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| 05 Aug 2013 11:00 PM |
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thanks for input, i appreciate it. |
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kogashuko
Basic Member
Posts:169
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| 03 Sep 2013 01:33 PM |
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There definitly needs to be a minisplit or ductless forum. I recently planned to go geothermal once my home addition project was completed. I even found a flow center I wanted to use on ebay for $200 which was a steal. I kept running across info on inverter driven heat pumps and how more efficent they were. I looked at a inverter driven geo but the price really put me off. I was also beginning to worry how I was going to lay all of the pipe. One day I happened to run across info on VRF systems that were ducted or ductless. I found a system for the addition that would work great at a fraction of the price. Best part is that it is inverter driven. Unlike my current heat pump system it would vary output depending on need. Right now I use the full capacity of my current systems maybe once or twice a heating or cooling season.
This system looks so good, and if it works out in the addition, I want to plan to install it in the rest of my house in small ducted units. A bit expensive but I could do the work a little at a time. I have also considered adding some dampers which would allow me to keep my current heat pumps in place for backup or in the case when it is very cold outside and I need even more heat. The other option would be to sell both units since they are fairly new. My mother is badly needing a second floor unit in her house at the moment and I could probably do a very quick swap for her. |
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joe.ami
Veteran Member
Posts:4377
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| 04 Sep 2013 07:19 AM |
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Yes I saw your comments on the general or design forums.
The split sounds like a good fit for your addition.
For heating dominated climates, ASHP's will likely never be more efficient than geo as we can design our minimum EWT while airsource is stuck with whatever ambient air temp mother nature offers.
That said geo is generally more expensive to install (unless compared to Altherma) so one has to compare cost v benefit. I encourage all to shop for ASHP's just as we suggest you shop for geo. Pick the right dealer. |
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Joe Hardin
www.amicontracting.com
We Dig Comfort!
www.doityourselfgeothermal.com
Dig Your Own Comfort! |
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