IrishSean Posted April 17, 2012 Report Share Posted April 17, 2012 Good morning, I was looking to see if someone could help provide me with some advice on my HVAC options. I live in an old 2 story twin with natural gas heat and AC. There are no returns from the second floor and only 2 supply ducts which run up walls in the kitchen. I am in the process of remodeling the downstairs and part of this was to remove one of the walls holding a supply duct. There really are no options for rerouting the duct as it is a stright run to the second floor bathroom. I figure my only 2 options are to have an awkward column in the middle of my kitchen or remove the entire duct. Also since I have no room to install a return duct, I was thinking I would install an attic based system to really improve second floor circulation. However, I believe this are only AC systems and I would still be left with no heat if I installed and attic system and removed the duct work running from the basement to the second floor. Is this correct? or are there systems that can supply both heat and ac? Thank you. Link to comment Share on other sites More sharing options...
hausdok Posted April 17, 2012 Report Share Posted April 17, 2012 If you've got central air it's probably already been configured as part of the air handling component of your gas furnace and uses the air handler of the furnace to move the cold air around. If the system is properly sized, it's probably not necessary to install a complete new system to the second floor, just improve air distribution up to the second floor and install a return air duct from the second floor back. If it's not large enough to heat/cool the entire house than you can explore a separate system for the second floor. There are lots of systems that can supply both heat and AC. Do you want it to be a heat pump system or are you interested in a gas heat/AC unit. Ultimately, you're going to need to talk to an HVAC guy who can determine whether the system you've got now is capable of properly heating/cooling the entire house; and, if not, can help you find the right setup for the attic. ONE TEAM - ONE FIGHT!!! Mike Link to comment Share on other sites More sharing options...
kurt Posted April 17, 2012 Report Share Posted April 17, 2012 Mike's right, you need another system if you want it right. What you got now can only be mangled into something unsatisfactory. You want a mini-split heat pump. I've done a few of these things now, and they are the future. Americans are resistant, but I think it's largely due to the unfamiliarity with the technology. Go here Check out the Hybrid Flex Inverter. Even the name is cool; sounds like Star Trek and dilithium crystals, but it's real. Read up, ask more questions. They're the future. Link to comment Share on other sites More sharing options...
IrishSean Posted April 17, 2012 Author Report Share Posted April 17, 2012 I do not have any room to run a return from the second floor thats kind of why I was thinking about an attic based system. My current system does suppy ac as well, there is just to ability to remove the heat. I believe the system is large enough. my house is only about 900 sq. ft. living space and the system seems alrge enough. Thanks Link to comment Share on other sites More sharing options...
hausdok Posted April 17, 2012 Report Share Posted April 17, 2012 I do not have any room to run a return from the second floor That's where I think you're wrong. If you've got a wall space where a supply duct can go up all you need is enough space to put a return next to itwith a layer of foam insulation between and then close it in a chase. If it's a 900sf house you aren't going to need that large a return or supply anyway. Around here i've seen them take the ducts right up through the second floor into the attic and then split the return air away from the supply air in the attic space. Talk to an HVAC firm that can figure that out for you. Check out the stuff Kurt's pointing you to. ONE TEAM - ONE FIGHT!!! Mike Link to comment Share on other sites More sharing options...
Marc Posted April 17, 2012 Report Share Posted April 17, 2012 If there is an open stairway, without doors, between downstairs and upstairs, then it'll function well as an air return. A ducted air return is redundant. Ductless mini-split is likely the smart choice for upstairs. Marc Link to comment Share on other sites More sharing options...
IrishSean Posted April 17, 2012 Author Report Share Posted April 17, 2012 If there is an open stairway, without doors, between downstairs and upstairs, then it'll function well as an air return. A ducted air return is redundant. Ductless mini-split is likely the smart choice for upstairs. Marc Link to comment Share on other sites More sharing options...
IrishSean Posted April 17, 2012 Author Report Share Posted April 17, 2012 Marc, what about in the summer? Link to comment Share on other sites More sharing options...
Marc Posted April 17, 2012 Report Share Posted April 17, 2012 Same answer. What difference does summer make? Marc Link to comment Share on other sites More sharing options...
kurt Posted April 17, 2012 Report Share Posted April 17, 2012 If there is an open stairway, without doors, between downstairs and upstairs, then it'll function well as an air return. A ducted air return is redundant. Marc No it's not. AC is about extracting heat as well as blowing cold air. Without an engineered return, AC performance @ the 2nd fl. will both blow and suck, and be decidedly sub-adequate. Mini splits are the smart design choice in situations like yours. Link to comment Share on other sites More sharing options...
Tom Raymond Posted April 17, 2012 Report Share Posted April 17, 2012 You've done enough demo and rework to remove a wall, why not do a little more and run new ducts? It'll cost way less than mini splits or a second furnace. Kurt, Americans are resistant to mini's because retrofits look like ass. Imagine line sets run all over the exterior like a bad cable TV install. Link to comment Share on other sites More sharing options...
kurt Posted April 18, 2012 Report Share Posted April 18, 2012 No it won't, and no, you don't have to have it look like ass. Americans are resistant to mini split systems. The old, wildly inefficient ways, will die hard. Americans are wedded to inefficiency; it's a way of life. Part of it is resistance to something hanging on the wall. Folks are completely fine with a 400 pound chunk of cast iron taking up floor space, but they don't like the thing on the wall. The whole idea is you can take old places and retrofit them efficiently, inexpensively, and have excellent performance. It doesn't always have to be the old way, and folks not able to blow big dollars get to play. Or, tear out more walls, retrofit sheet metal, increase scope and cost exponentially; that's fine for lots of folks if that's what they want. Link to comment Share on other sites More sharing options...
IrishSean Posted April 18, 2012 Author Report Share Posted April 18, 2012 Same answer. What difference does summer make? Marc well if heat rises and cold air decends and my biggest problem is cooling the second floor in the summer, then what good does air moving thru the stairs do me? Link to comment Share on other sites More sharing options...
IrishSean Posted April 18, 2012 Author Report Share Posted April 18, 2012 You've done enough demo and rework to remove a wall, why not do a little more and run new ducts? It'll cost way less than mini splits or a second furnace. Kurt, Americans are resistant to mini's because retrofits look like ass. Imagine line sets run all over the exterior like a bad cable TV install. Kurt, I have a small house and the remodeling I am doing is removing nearly all the 1st floor interior walls. I know this sounds odd but it's true. My house is an 80 yr. old 2 story twin. I really have no room to runs ducts, which made me think of an attic based system. It's crazy cause I would then have 2 systems to heat and cool a house of less than 1,000 sq. ft Link to comment Share on other sites More sharing options...
hausdok Posted April 18, 2012 Report Share Posted April 18, 2012 the remodeling I am doing is removing nearly all the 1st floor interior walls. [:-bigeyes (Backing away very slowly now.) ONE TEAM - ONE FIGHT!!! Mike Link to comment Share on other sites More sharing options...
Marc Posted April 18, 2012 Report Share Posted April 18, 2012 Same answer. What difference does summer make? Marc well if heat rises and cold air decends and my biggest problem is cooling the second floor in the summer, then what good does air moving thru the stairs do me? Before conditioned air can exit the registers in the upstairs room, air must return to the air handler. I don't quite understand what Kurt is trying to say. If you've an air return grille at the air handler that is large enough to handle the entire system air flow then you don't need an additional return upstairs, unless a door blocks the air return path between floors. As for the 'hot air rises, cool air sinks', of course, lotsa multi-story houses have that problem. A local temperature sensor installed upstairs should fix that. You can accomplish that by either installing a zoned duct system or additional independent HVAC system upstairs with it's own thermostat. If you go with a separate system, mini-split ductless would likely be best depending on your floor plan. Now if what you have in your house is a distributed air return duct system in which each room has it's own air return grille then none of what I've said in this thread applies. Distributed air return systems in houses are rare in my area. Marc Link to comment Share on other sites More sharing options...
IrishSean Posted April 18, 2012 Author Report Share Posted April 18, 2012 the remodeling I am doing is removing nearly all the 1st floor interior walls. [:-bigeyes (Backing away very slowly now.) ONE TEAM - ONE FIGHT!!! Mike we are putting a beam up for the load bearing Link to comment Share on other sites More sharing options...
Charles46 Posted April 18, 2012 Report Share Posted April 18, 2012 When you are working on a project such as you are, one of the best things you can do is acknowledge you don't know and to seek advice, which you are doing. The best and most consistent advice you have been given is to check with a HVAC person. Why you did not do that first is a question only you can answer, and only you need to know the answer to. Were it me, the person I would have asked for advice would be the company that services my HVAC system in the spring and in the fall. They are the ones that know your system, that know your house, that want to maintain and retain your business. Unless of course you do not have your HVAC system maintained on a regular basis and that becomes another issue. Link to comment Share on other sites More sharing options...
Charlie R Posted April 18, 2012 Report Share Posted April 18, 2012 I've seen a couple of renovations of 100 year old row homes in Baltimore where they used the mini-split heat pumps - the one had 5 interior zones. As far as I could see they worked quite well. The homes originally had gas or oil fired boilers with no A/C units. Link to comment Share on other sites More sharing options...
IrishSean Posted April 20, 2012 Author Report Share Posted April 20, 2012 Kurt, I just wanted to ask if you preferred the Fujutsu system or you provided it just for informational purposes. I am getting 2 estimates from their contractors next week but I was thinking about getting one from the Mitsubisji contractor as well buth thought maybe the Fujitsu system was better. Link to comment Share on other sites More sharing options...
Steven Hockstein Posted April 20, 2012 Report Share Posted April 20, 2012 When you are working on a project such as you are, one of the best things you can do is acknowledge you don't know and to seek advice, which you are doing. The best and most consistent advice you have been given is to check with a HVAC person. Why you did not do that first is a question only you can answer, and only you need to know the answer to. Were it me, the person I would have asked for advice would be the company that services my HVAC system in the spring and in the fall. They are the ones that know your system, that know your house, that want to maintain and retain your business. Unless of course you do not have your HVAC system maintained on a regular basis and that becomes another issue. I agree. Most heating and air condioning contractors will give you free estimates in the hope of getting the work. Get a few different opinions from specialists that actually see your home. They are likely to come-up with some creative options. The bottom line is that you can have the most beautiful space in the world but if you are not comfortable, you won't enjoy the space. Get a professional to help you. Designing your HVAC system with the help of strangers on the internet is not your best option. Link to comment Share on other sites More sharing options...
hausdok Posted April 20, 2012 Report Share Posted April 20, 2012 Hey! What strangers? We're all family here. [] ONE TEAM - ONE FIGHT!!! Mike Link to comment Share on other sites More sharing options...
Steven Hockstein Posted April 20, 2012 Report Share Posted April 20, 2012 Hey! What strangers? We're all family here. [] ONE TEAM - ONE FIGHT!!! Mike I meant strangers to Irish Sean, not each other! [:-monkeyd Link to comment Share on other sites More sharing options...
kurt Posted April 20, 2012 Report Share Posted April 20, 2012 Kurt, I just wanted to ask if you preferred the Fujutsu system or you provided it just for informational purposes. I am getting 2 estimates from their contractors next week but I was thinking about getting one from the Mitsubisji contractor as well buth thought maybe the Fujitsu system was better. Do what Steve said. Talk to lots of people. Not seeing it, it sounds ready made for a mini-split. But, folks in the house might see something I can't, and come up with a better idea. The technology has been around for long time, but the last 5 years has seen some remarkable upgrades and advancements in overall design engineering. We've done a few of them now, and the more I work with them, the more I like them. They're the miracle of modern HVAC systems. The hold back is all mental; people think there has to be ducts and pipes and giant centrally located equipment. They're wrong. Link to comment Share on other sites More sharing options...
edwardh1 Posted April 21, 2012 Report Share Posted April 21, 2012 Mini splits are really really popular in the caribbean islands, and in new high end construction around here, especially for mother inb law suites or rooms over garages. Caribbean units are quiet and have infinetly variable air speed with remote control. I thinkj "Mericans" are afraid of them because of the motel units in the usa that are very very loud and usually clatter and thump when they shut off, they think mini splits are motel units and I have seem HVAC people try to sell the motel units, Mitsibishi invented them but there are many other mostly Japanese or foreign brands, sanyo, etc. I like the ones I have seen Link to comment Share on other sites More sharing options...
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