Updating From Oil/Steam to Hybrid Heat Pump in MultiFamily Building
Hi there, hopefully someone with more knowledge in this area can offer some guidance.
I have a 4 story, 6 apartment building with a store on the ground floor. Currently there is an inefficient oil boiler (~30 year old) and a steam system. Costs are too expensive, as you can probably imagine.
The apartments are subway-type apartments, 600 sq feet in size, with 4 windows. There are current 2 radiators at each end of the apartment on a single pipe steam system.
I would certainly prefer to offer to Tenants the ability to control their heating and preferably have them pay as much of their share as possible. Doesn’t have to be the entire cost, but at least some part of it so they can have a significant incentive to use heat rationally.
Thus, I am looking at a hybrid heat pump solution. Because of the layout of the apartments, there would be 2 heat pumps in each apartment, each being on either side.
I have already ruled out air based heat pumps because temperatures can get pretty cold on some days, here in New York City. Also because I prefer an abundance of heat rather than j ust enough of it.
So the alternative is a water sourced heat pump. I’m not entirely clear on how it works but from what I understand it requires me to supply to each heat pump a source of warm (85F) water. No problem with that, as I can install a high efficiency gas water boiler in the basement. I would replace the current steam pipes (at each corner of the building) with 2 smaller diameter water risers (same location; at each corner).
I assume that Tenants would share the partial cost with me; I would pay for the gas water heating and they would be the electrical costs associated with running the heat pumps in their apartments. This is exactly what I’m looking for.
The vertical heat pumps (Whalen) that I’m looking at seem just small enough to fit where I want them to be located.
Has anyone done something like this? What are the chances this will work, and work well at heating the apartments? Any better ideas?
ayla.yavin
in Heating and Cooling 8 years and 4 months ago
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17 replies
agdipierro
in Heating and Cooling 8 years and 4 months ago
Try VRF heat pumps with Advance Heating Technology. Contact Misubishi for info, then price other brands as well.
ellenlourie | 8 years and 4 months ago
In heat pumps water cool/heat condensing side applications, boilers are warming condensers in heat mode, and working at 100F area water temperatures, with near 100% condensation rate and 98-99% boiler efficiency.
Also, in heat pumps water cool/heat condensing side applications, heat and cool are exchanged between rooms, hot room can dump heat into colder room and versa versa, with no boiler participation.
reuventenam | 8 years and 4 months ago
In today’s world heat pumps are the way to go. utilizing a hot water boiler to feed to a heat pump is costly but worth it as long as you can afford it. The best part is the split system for the AC in the summer. I am a plumber for a long time and believe in moving forward with better efficency and lower carbon foot print. But in the end money rules.
steam_man | 8 years and 4 months ago
Turn down the system pressure. Your vents are closing due to high pressure, steam is getting trapped, condensing, turning to water and then when the pressure drops, the vents open and the water gets pushed out on the next firing cycle. Turn it down. You’ll save fuel too.
ayla.yavin | 8 years and 4 months ago
Regarding the steam vs hydronic discussion – I have steam in one building and hydronic in another.
The steam system drives me nuts! Last year I decided to replace 90% of the radiator vents to HeatTimer vents and now, a year later, about 1/3rd of them are leaking and making hissing noises.
The hydronic system on the other hand is awesome! Even at full blast the radiators are completely silent – put your ear near the radiator and you can barely hear the water flowing.
As for efficiency – it’s hard to tell because my steam system runs on oil while the hydronic runs on gas. The former expenses are about 3x to 4x the later (granted, the steam boiler is older – but all electronics including pump, atomizer, igniter, and control unit have been replaced new).
Many people who have been in the industry for a long time seem to have little experience with alternative HVAC systems and tend to base their recommendations based on their experiences, which usually deal with traditional furnaces running on oil/gas. Very few know much about heat pumps and simply shrug when I approach them with a detailed question about them. So as you can expect, they say the cheapest improvement would be to keep steam but definitely replace the boiler and convert it to gas. The other (and only alternative) option is to replace the boiler and also convert the steam system to hydronic.
Since I really dislike the steam system I am very tempted by their second recommended option since I have experience with hydronic systems and know what there is to gain. But that is a cost of about $15k for the boiler plus another $30k for the hydronic risers and new (bigger) radiators (plus also fixing back parts of walls and ceilings).
But I also hear plenty good things about heat pumps from those who deal with them day to day. Like I said earlier, there is a very visible trend in the neighborhood of high-end renovated apartments being disconnected from building wide heating systems and converted to individual heat pump units. Haven’t seen anyone complain or go back from heat pumps to furnaces.
If I was going to go with the heat pump, I’d more than likely choose the Mitsubishi City Multi system. Got a rough estimate from this one guy for $50-55k with units and electrical work included in price, minus removal of existing steam system and risers. I still need to know how much one should expect to pay in electricity costs on a per apartment basis while the system is running. He says Mitsubishi offers a long term warranty on both their indoor and outdoor units and maintenance is probably not much more than what it cost me to maintain my oil boiler. Heat pumps are basically the same technology as in refrigerators, and those don’t break often, right?
Regarding how to deal with convincing Tenants to agree to pay for their heat usage – from what I know, this would be a decreased services agreement requiring a decrease in rent. It is fair for both sides. What the landlord loses in income, he gains equally (or just about) in lower expenses. Plus fewer heat related complaints to deal with in the winter. Plus a good share of the heat pump installation costs would be covered by an MCI as it benefits everyone in the building.
So as you can probably tell, I’m tempted more for the heat pump than a hydronic and gas conversion. With the later I still have to keep an eye on apartment temperatures in the winter whereas with the former I can basically go on a winter long vacation and let the Tenants control the heat themselves (on their cost).
ellenlourie | 8 years and 4 months ago
I forgot to mention. Steam systems cannot be zoned, but with trvs there is an option to set individual temperatures in each room, independently.
In high efficiency hot water systems zoning is not working and kills system efficiency, instead you will need to create loops with individual outdoor reset motorized 3way valves, you don’t even want to know the cost of this, or install trvs as well.
ellenlourie | 8 years and 4 months ago
Yes, this is my statement. Properly done steam system, and I stress word “SYSTEM” will be as efficient as hot water system with condensing boiler installed. We usually install Viessmann boilers for hydronic, I personally love them, but I would never recommend replacement of steam system with hot water one, it is just waste of money. Regarding 82% vs 92% I have yet to see these 92% at combustion analyzer display. Top 87% and then some condensing if your system is designed properly and you should not forget pumping cost. You also have to look at efficiency of the system not at fictitious boiler AFUE efficiency.
brucef | 8 years and 4 months ago
Yeah, but.
Steam system may be dumber, but not necessarily less efficient or more costly.
No circulator pumps, no zone controllers, no more teachers dirty looks.
Would I spec a steam system if I was building new, probably not. Radiators and risers would be too expensive, but you already have them.
I would stereotype the hydronic stuff as pretty reliable, easily serviced by average techs. Maybe setting the upgraded steam system might require an experienced hand.
But once up and running, it should have very low maintenance cost. No moving parts, almost no electronics to fail.
In contrast, all your high tech solutions will likely test their warranties.
Your imagined 2% savings will look small when tenants are calling no heat and a technician who can fix it has to fly in from Texas.
cmu | 8 years and 4 months ago
Gennady, how do you say that when 1) steam systems cannot go above 82% efficiency vs. up to 92% for a condensing system (thereby an immediate 10% savings,) 2) steam systems have a higher vampire loss due to higher temperatures and 3) they cannot be zoned, so in OPs 10 units it will take a seasoned expert to balance the system?
That said, to OP, airsource heat pumps are almost always variable speed nowadays (I have a $1400 12bku unit that is.) In our climate, Mitsubishi or LG standard units might work (down to 15deg), when they turn on the strip heat elements and quadruple the running cost. Low temperature heat pumps cost more of course, and are even used way north of here. You need a good consultant to set up your ROI for this plan.
Augustiner | 8 years and 4 months ago
Hydronic gas fired with new good controllable radiators is the best. if you like you can get BTU consumption tenant metering and adjust the bill at the end of the year. It’s not a common practice in the US, but used for decades in Europe.
And while you’re at it – get a big dual heat exchanger tank and mount a couple of evacuated tube panels on your roof to supplement hot water production of the system. There are tax credits available for switching to gas (i think) and solar thermal installation for sure
ellenlourie | 8 years and 4 months ago
Properly set up steam system can compete in cost of heating and comfort with best high efficiency systems on the market. No need to convert from steam to hot water or heat pumps.
brucef | 8 years and 4 months ago
Time to stop your research and rethink where you are trying to go.
Any “new-fangled” equipment will be hawked by the manufacturers, but too technical to install/source/support in NYC, especially a retrofit for a small project.
Maybe not what you wanted to hear, but there is good news.
I can tell from your posting that you are a forward thinking, solution oriented individual.
You are barking up the wrong tree. We install and support multiple geo-style systems.
Being a landlord is hard enough without pushing new, unwelcome expenses onto tenants. (I have 40 years experience on that)
I trust your aim was to unload some of the expense from yourself and shift it onto someone else (your tenants). If done intelligently, you should be able to re-engineer a steam system so that the expense is greatly reduced. Or shift to hydronic risers.
But your ROI might be 2-5 years, after which you save money every heating season.
And that’s with you paying for everything.
All sorts of new equipment will set you back plenty. Even if you shifted 100% of your energy costs onto your ten ants (and they won’t be happy), you still have many years before you could pay off all the new equipment. If ever. Plus your maintenance cost on that fancy stuff after warranty is all on you.
Trust me, even during warranty, the manufacturer credits us the cost of the equipment, but your original installer has to pay for his labor, which if you are still on speaking terms (which I doubt), will be like pulling teeth. PLan on paying.
Hopefully before then you will re-focus your “energies”.
ayla.yavin | 8 years and 4 months ago
@castafiore002 Thank you for pointing out VRF systems. This is quite possibly the best solution I’ve come across so far.
Also I didn’t realize how much extra equipment is involved with WSHP systems. So WSHP is removed from my list.
Turns out I luckily have a 3-phase electrical supply to my building so the load of one of these VRF outdoor units shouldn’t be too taxing on the main line, right?
I’ve done some quick and dirty heat loss calculations: per apartment, there is a heat loss of 4,000 to 6,000 BTU (80-90% of which is lost thru two double glassed windows at each side of the apartment). Do you know how much heating BTUs are needed to ensure adequate heat given these loss numbers?
nick521 | 8 years and 4 months ago
Water source heat pumps (WSHP) are air-conditioning systems that can also heat in the winter. They use condenser water as a heat sink (summer) or heat source (winter). The condenser water loop can be supplemented by a boiler for the winter. You will need to add a cooling tower on your property to produce condenser water . You will be adding cooling tower, pumps, piping and increased maintenance; this is cost prohibitive. WSHP are usually used in high-rise commercial, residential or hotels.
Your best bet is to replace and upgrade your boiler with a gas-fired efficient boiler, in lieu of stream, a hot water system, replace your radiators and add thermostatic radiator valves, tenant can control their heat.
If you want to forgo your boiler system, instead of WSHP, consider a VRF system (variable refrigerant flow) with energy recovery. Similar to WSHP, you can have ducted or ductless indoor units or cassettes, you will have one or two air-cooled condensing units for all the indoors units. VRF are similar to the traditional split system, except that they are more energy efficient and you don’t need one outdoor unit for each indoor unit, one outdoor unit can be connected to up to 16 indoor units. Check Mitsubishi City multi , Daikin or LG VRF systems. You eliminate your boiler, as it does heating and cooling.
My three cents.
B.
ayla.yavin | 8 years and 4 months ago
I’m not entirely sure on the specifics, but I do know that some of the high rises on the East River on the Brooklyn side have Whalen heat pumps providing both heat and cold air. I believe they are water sourced and get their warm water from a central boiler source likely on the roof.
My idea for the water sourced heat pumps was to run just two risers (shared by all heat pumps in that vertical corner of the building) in each corner of the building. Doing that should not cost much money since it’s just two long copper pipes going up straight from the basement.
But after speaking with someone just now, I was informed that most luxury renovations (even in old brownstone buildings) are moving to ductless heat pump systems. This looks very attractive initially because there is no need to run any risers nor have any boiler in the basement (except for standard bathroom and kitchen hot water, which is unrelated).
With ductless systems, I have two concerns: performance during polar vortex weather in the winter and electrical consumption. Apart from that, installation should be ve ry simple by mounting the outdoor unit on the exterior side wall next to the apartment window and routing thin lines to the indoor blowers. But apparently, these must not be real concerns to the professionals since heat pump systems are being installed all around my neighborhood these days for a while now.
My main goal with a heating retrofit project is peace of mind (no Tenant complaints and no worrying about thermostat settings) as well as low costs. I’d rather lower the rent just a slight bit to get them to agree to this than spend another 25 years with steam heating if I were to just replace my existing boiler.
Back to heat pumps, I’m looking at Trane mini-split ductless heat pumps. If they can provide ample heat when a polar vortex arrives as well as keep electricity costs reasonable, this will probably be my best choice for a replacement heating system.
Ideally, I hope someone with experience in heat pumps in NYC can chip in to this discussion…
cmu | 8 years and 4 months ago
Oh noticed you said ‘supply warm water’…from a gas furnace. That’s *not a heat pump* then, it’s just a hot-water radiator. Which are you considering?
cmu | 8 years and 4 months ago
Seems extremely expensive to place 14+ heat pump units. And urban water-source heat pumps use an *insane* amount of water, which is just piped in & discarded, Your water bill will be thousands unless the Whalen unit works differently. If, please explain, I’m interested in finding out.
I suspect you’re thinking of ‘water-source heat pumps’ like geothermal, where (in the ‘burbs) ground or pond water is used as the heat/cool source, so there’s no waste of water.
Heat is expected by most tenants, and you’d be hard pressed to get your investment back unless you raise rent (and have you noticed, rents are dropping a bit?)