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LifeBreath HRV

Paul,

When you add the duct heater/controls to both the install and operating costs, how does it end up stacking against the Sterling Ultimate Air ERV. Since there is no water to condense, freezing would not be a problem, and with 90+% energy transfer, it should not need any tempering.

There's this rule of thumb that you use HRVs in cold climates, and I can't figure out any reason for it. It used to be that they were more efficient than ERVs, but the Sterling unit changes all that.

jerry

Comments

  • Steven_4
    Steven_4 Member Posts: 23
    Do we need a duct heater?

    WE are building a SIP home and have purchased a Lifebreath HRV 200max. It arrived the other day and we gave a copy of the insalation manual to our contractor (who had never installed one). When we spoke to Mike Allen the tech guy from the company he told us we would need digital electric timers and a dehumidistat. Now he says that we need a duct heater or the incomming air during the winter will be around 40 deg. I thought that the hrv warmed the air? Who can i talk to about designing a system for our house? Can we use anything smaller that 6" ovalized ductwork?
  • Constantin
    Constantin Member Posts: 3,796
    I would talk to...

    ... Rob at NRT.Radiant, as he probably has a lot real-life experience with these systems in very cold environments.

    Our home has two Lifebreath TRVs and I don't expect to have any issues. Given the probable tight construction and thick insulation of your SIP, I doubt you will have much of an issue either. We put motion sensors into our bathrooms that make the TRVs kick into high gear during occupancy + 10 minutes. The rest of the time, they loaf at minimum speeds. Look into occupancy sensors at Leviton Lighting and you'll see what I mean.

    As for the incoming air temp, depending on the speed of the fan it might get cold. But it's all a question of volume of cold air coming into the home vs. the warm air inside. After all, there are plenty of folk who are toasty warm in very leaky homes thanks to large heating plants and lots of fuel. Given that you can plan for the impact of exchanging air by adjusting the infiltration rate in your heat loss calculation, I would simply do that and worry less about the incoming air temp unless the exhaust is right over your bed.
  • Paul Pollets
    Paul Pollets Member Posts: 3,656
    Controller..

    Use the Lifebreath Programmable Ventilation Controller (PVC). It has a built in dehumidistat, and is easy to wire into the air handler.

    Installing a Duct heater to temper incoming fresh air in the winter would be recommended. When it's 20 below outside, the unit will not be able to overcome the ambient temperature...you may get icicles on the coil.

    Reducing the duct size is not recommended. Follow the manufacturer's instructions for duct design. Oval duct can be used...insulate all ducting for best performance.

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  • Steven_4
    Steven_4 Member Posts: 23
    Paul

    What instructions? I don't see a required duct sizing. My builder would like to see a smaller duct so there aren't huge holes in the TJI's but I guess I'll wait and see what our contractor says. This will be a first for him and us.
    I'll probably try and call Rob for some help.
  • Blackoakbob
    Blackoakbob Member Posts: 252
    The 200max.....

    should have a built-in controller on the right side. This control has a dehumidistat with an adjustable dial. This control will sample air passing thru from the house. Set it between 50 & 20 and adjust to your comfort level. You can set the fan to operate at different speeds by pushing and holding the small pad on the control. I use the 20-40 setting as the unit runs 20 minutes out of the hour sampling the air in the building. When necessary, the timers you place in the bathrooms will bypass the control and run the unit on high for the set time. Also this unit has a built-in defrost mode which allows building air to recirculate inside the unit to clear any frost that accumulates. Just by plugging the unit in and with the door switch held closed by a clothes pin you can observe the test mode of the controller as it cycles thru all modes of operation. Use six inch duct throughout and use adjustable grills on the exhaust side to balance the air in to the unit. You will be amazed at the fresh, clean, spring-like air in the home! Hope this helps, Best Regards.
  • Paul Pollets
    Paul Pollets Member Posts: 3,656
    download

    from the lifebreath website and get the installation/sizing guide from the rep.

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  • Paul Pollets
    Paul Pollets Member Posts: 3,656
    LifeBreath vs Sterling

    Jerry, I've never used the Sterling unit. I've been using LifeBreath since '92. I'd ask the rep for clarification. Incoming fresh air needs to be tempered, when outdoor air temp is below 30 degrees.

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  • JohnWood1
    JohnWood1 Member Posts: 63
    ERV vs HRV

    HRV is a sensible HEAT recovery ventilation device. It is designed to pass the Latent energy, ie the moisture out of the house, therefore why it is used in low temp environs. An ERV or an ENERGY recovery ventilator the other hand is designed to return the entire energy load, both the sebsible and the latent back into the structrure, or in the case of a high humidity cooling dominated environment, to return the heat energy back to the outside, reducing the load on the A/C whaile allowing ventilation.

    In short........ if you are installing in a heating dominated area, you want to install an HRV and in a humid cooling dominated area, use an ERV. If you use an ERV in a cold climate you run the distinct possibility of freezing the "core" and damaging it beyond further use.

    As to adding supplemental heat......... again, use your head. If you have a heating system that is at it's limit at design, you should definately install a duct heater as in very low temp conditions you do have some inherent loss of energy from the structure. Also where are you bringing the air into the structure? Will it impinge on the inhabitants?

    Ductwork............. If you are new to ductwork GET HELP IMMEDIATELY! You would not give a boiler and tube to an electrician would you? Or a heart to transplant to your plumber............. So get EXPERT help with the duct sizing. Most wholesalers who sell the stuff SHOULD be able to size the airside for you. If not find some one who will.

    Lifebreath is a fine product...... probably the best. BUT as with any fine product, you need to know how to size and install it.

    nuff said.
  • Matt_21
    Matt_21 Member Posts: 140
    paul

    would i be better off with a lifebreath hrv or turbulet flow precipitator? i was thinking of the tfp for the winter months. last year the kids were sick most of the season and i was thinking of hepa filtering the air. my house has radiant floor heat so i was thinking of hooking it up to my first floor air handler and letting it run when the humidifier called the air handler on. what do you think?
  • Paul Pollets
    Paul Pollets Member Posts: 3,656
    TFP v HRV

    The HRV ventilates and exchanges air, the TFP filters the air stream. Install the HRV and add the TFP as an option.

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  • joel_19
    joel_19 Member Posts: 931
    whoa

    You purchased the unit and the installer has ever seen one ?
    I don't mean to sound rude but who is designing the HVAC system for your house ? . This is an intergral part of a SIPS house and the design/install contractor should of had this in his design , supplied the unit he felt appropriate and should be knowledgeable in its's function , sevice etc. your question about downsizing the duct instantly scares me . The only answer any good HVAC contractor should of had for that is "No" . Proper airflow is where the gods live in ductwork it should all be sealed and insulated , avoid lots of sharp bends , flex duct etc. it's not something that can quickly be covered in a forum such as this .

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  • Matt_21
    Matt_21 Member Posts: 140
    what does SIPS mean?

    i'm assuming it is something insulated panel system?
  • joel_19
    joel_19 Member Posts: 931
    yes

    Structual , Insulated , Panel , System . The term is frequenty used even in post and beam home where the panels typically aren't truly structual.

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  • Just to add to your post john, Venmar makes cold-climate ERVs (Canadians, dontcha know, they sure know cold!) that we use all the time, lifetime warranties on the core and automatic defrost capabilities as well. I believe during extreme cold snaps they will basically not be exchanging very much due to the automatic defrost, however such periods are usually pretty short lived even in our region.

    I have seen such systems in the past with noticeably cold air at the fresh air supply ports, and since most exchanger's exchange efficiency is somewhere around 70%-80% I believe, that stands to reason.. with a 40 or 50 degree delta T, that's quite a bit cooler returning to the house after the exchange. However, properly mounted ports with low continuous flow usually are not very noticeable in that respect; it seems that the problem is usually when people are skimping on ports and thus have greater airflow from fewer places.

    To the original poster; lots of sickness in the winter would probably be taken care of just with regular ventilation; it's probably noxious gas buildup in the house and/or excess humidity more than anything else, it causes all kinds of respitory problems. I wouldn't worry about HEPA filtration unless you or your family has severe particulate-related problems (allergies to pollen, for example, which wouldn't be a winter problem); fresh air is *probably* all you need.
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