Heating Large Spaces

Topic: 
Heating and Cooling
Question: 

I was asked to install heating in our local church. The church is 85 ft. by 55 ft. by 46 ft. high. I am thinking of warm air heating because it is economical. Do you think it will work? Please see if you can help us as we are not too familiar with this type of heating as most homes here heat with hot water boilers. Thank You

Answer: 

This is not a simple project due to several factors:

  • The size and height of the building requires a system that gives you a relatively uniform temperature throughout the space. The last thing you want is a heating system that gives you 90F air at the top of the ceiling and cold feet at the floor level. In a building such as yours, a very important part of the system would be the "return air" portion of the system that collects the over heated air at the 46 ft. level and brings it back down to the floor level.

  • You will also want a system that can be turned down when the building in not in use and heat up relatively quickly at other times.
  • Some industrial (factory/warehouse) forced air heating systems use fast moving heated air from wall mounted furnaces. These work quite well in places with people who are active and where noise is not a factor.

    One option might be a radiant floor heating system. The hot water coils could be placed inside the floor joists (if any) or in a thin layer of concrete that is installed under a new floor surface. The advantage of such a system is in placing the heat under the folks in the building. Such a system could even be designed in zoned area with the sections of the building in use being heated and other sections at a lower temp. You might want to contact Warm Touch and talk to them about some of their radiant systems

    George

    Joseph:

    I hope that I was able to provide you with some help regarding this project. On a more personal note: I was born in Jerusalem and hold dual US and Israeli citizenship. Over the last years I have been a local (Seattle) member and contact person for Americans for Peace Now.

    As such, I was particularly pleased to see a questions from Ramallah.

    My best wishes to you and your congregation, Shalom, Salam,

    George

    Hi George,

    I am the guy from Ramallah who wrote requesting some information or rather advice from your company. I am sorry for not thanking you for your response earlier but since I was able to get more information which you may be able to help me reach a proper decision.

    First of all I found out about your service by just surfing Yahoo and search for Heating, Air Conditioning and Warm air Heating. Your offer of free advice popped up so I decided to benefit from your experience in the heating business. As you may recall, I asked you for the best type of heating to heat our church which is 85ft. long, 55ft. wide and 46ft. high. From my experience in California, I knew that churches and places of worship are normally heated by Forced Warm Air through ducts under the pews. If for no other reason, at least it has lower running costs which we are very much interested in, especially since our parish is struggling to make ends meet. Anyway in our case we don't have a basement under our church, so we have to remove part of the tiles under the pews and place the ducts and re- tile. I asked Oran company in West Jerusalem and the partner whom we have known for a long time came over and suggested that would be perfect but when we tried to find a Diesel or oil run furnace with a capacity of 10,000cfm fans we found none locally or in the States. Oran found Lamborghini Company in Italy produce ones of that size but on further investigation we found out that they are engineered for free air movement and not through ducts. In other words they lack the capacity to push warm air through 60 metres of ducts.

    Meanwhile a cousin of mine in the heating business who studied at U.C. Burkeley suggested ducts with boilers and the purchase of Air Handling Unit. The problem with that is the cost of each unit capable of 10,000cfm. It is around $19,000.00 and since we need two of them, the cost will become out of reach for us. We have a budget of around $30,000.00 and we want to spent it wisely to resolve our heating problem.

    Also another suggestion was given to us which involves Trane Gas- fired self-contained rooftop unit model #YCH 350 which has the ability to Aid condition as well. It has the capacity of 102kW for cooling and heating capacity of 119kW. What is the feasability of a system like that if put on floor level outside of the church walls and connect it to the ducts. We would need two units to carry the load, so we will have one on each side of the church. There is concern about noise, and I suppose they have to be installed far away from the walls of the church. What do you suggest?

    George, as far as the system you suggested, it sounds great, especially since they have plastic type of hose for this purpose instead of copper tubes, but to take the whole floor of the church, do the work and retile would cost well over our finances at the moment. I hope that you will be able to help me reach a decision on this matter. Look forward to hear from you on my e-mail address. Thank You,

    Joe

    P.S. I am happy to know that you were born in Jerusalem. I want to tell you that Jerusalem is my place of birth as well and for that you and I should do all we can to work or atleast pray for peace in our portion of the world.

    Thank You

    Hello Joe!

    Nice to hear from you. Your first question talked about heating the church, in your reply you are also talking about cooling. If your primary requirements are for heating, then I would explore the possibility that a "focused" heating system might work just fine for you. Let me explain:

    Heating your entire church requires a massive system, and as you point out, a system that does the job quietly. Such a system could also be used for cooling but is very expensive. Your heating needs may not require a system that heats the entire church. I am assuming that on days when the entire building is used for services, your heating needs are partially offset by the large amount of heat produced by the many people in the building (am I correct about that?).

    Your heating requirements are most probably greater on days when a smaller number of people use the church: fewer people, fewer warm bodies but the same large space. On such days, a smaller "focused" heating system might work. Such a system might involve isolating a portion of the church and heating just that area. It might also involve radiant heating systems that are designed to heat the people and not the whole building.

    You may have seen some gas heaters that are used in outdoor cafes to heat the people who are sitting outdoors in cool weather. You may also have seen some of the Roman excavations or Turkish baths with floor heating systems. These are all examples of radiant and/or "focused" heating systems that are designed to heat people without heating the entire environment around them.

    If, for example, your biggest needs are to heat the the smaller number of people who attend your church on non-holiday occasions, then it might make sense to install a radiant heating system in one area of the church. Such a system might have to be turned on an hour or so before the services and could then be turned off at the end of the services.

    I am not sure that any of this makes any sense in your case, however, I do think that you will have to start with a clear idea of your needs: heating (when and how much), cooling and the relative importance of each.

    By the way, with 46 foot high ceilings, my guess is that cooling could be done