Spurred by student initiative, this Minnesota magnet school has become the host for a unique collaboration focused on auditing and improving its mechanical and environmental performance. See how the partnership has gotten off to a solid start in conducting what is far from your average extra credit assignment.

Temporary HVAC is needed in buildings for a variety of reasons — severe weather, natural disasters like earthquakes, power outages, equipment failure, or just preventative maintenance downtime. When the heating or other HVAC functions go out in a building, the occupants will likely become unproductive or may not be able to function at all.

Heating for freeze protection is generally the focus in an emergency; however, depending on the building type, there may be an equally important need for cooling, humidification, dehumidification, filtration, and/or ventilation air. Having a plan for getting a building’s HVAC systems in operation with temporary HVAC equipment in a timely manner avoids stress and the downtime which can impact a business’s bottom line. Having temporary HVAC in place before a competitor may give a business the opportunity to help their customers and gain more customers, too.

Building management can be prepared with some basic strategies that can be put in motion with a few quick phone calls when these situations occur if there is a plan in place. The logistics of putting temporary HVAC equipment in place takes a considered plan that allows for fast response time and assurances that equipment will be available and ready.

Responding to a Crisis

A crisis is not the time to start thinking about temporary HVAC. A crisis is a time to execute a plan without having to look for a source of equipment or determining the capacity of equipment required to keep the essential parts of a building in operation.

Problems that can be avoided with proper planning can include things like availability of equipment from a local supplier, having the proper power and fuel source(s) ready for hookup of the equipment, knowing the critical base-load so as not to over- or undersize the temporary equipment, understanding the peak weather conditions of the facility locations, proper venting of fossil fuel fired heaters, and understanding and agreeing on the risk of installing temporary equipment.


Understanding the specific applications and needs of various building types is essential to proper equipment selection.

Construction companies sometimes need temporary HVAC during construction to provide the proper conditioning of spaces once a building gets to a certain point in the process. The permanent HVAC equipment may not be available or the building owner is not willing to allow the use of the equipment by the contractor due to product warranty time limitations or other reasons.

Natural disasters such as earthquakes, hurricanes, tornados, or severe weather conditions may cause major power or utility disruptions for hospitals, outpatient healthcare facilities, and emergency operations facilities. These types of buildings will generally have redundant equipment from the beginning, but there are older and smaller such facilities that do not have the luxury of a full stand-by redundant system.

Military or other governmental facilities will likely require some level of temporary HVAC in a situation where a community is unexpectedly in need of assistasnce.

Essential community businesses like grocery stores, service stations, and banking facilities may not generally think ahead and plan for temporary HVAC and utility services when they build their facilities. These businesses are needed and can actually increase their business opportunities if they have a plan in place to stay operational when other competitors are not able to do so.

Sporting venues and schools facilities may not have a need for investing in temporary HVAC services unless they are part of a larger community-wide emergency plan and are needed for things like sleeping quarters as part of disaster relief.

Restaurants and small businesses may or may not have a desire or need to stay operational at all times, but having a plan in place may be desirable as a minimum part of the facility management thought process. With restaurants, there is an added degree of complexity for the cooking equipment and supply and exhaust air systems affiliated with the cooking process.

Industrial facilities at times need temporary HVAC, too; however, the equipment needed will likely be more complex and larger than in other types of buildings if the process area of the plant is being served. Heavy industrial facilities may or may not be able to function without temporary HVAC services depending on the processes involved. Processes that require a large amount of refrigeration or ventilation may simply be at a loss to stay fully in operation.

Some applications may be suitable for serving with portable units in the building whereas other applications may require units to be mounted on the ground and ducted into the facility. Whether it be boilers, chillers, fans, air handling units, or generators there are businesses that provide temporary equipment.

Developing The Plan

In many respects, the process of determining the capacity and need for temporary HVAC equipment for a facility is similar to going through a building design process. It may be wise for facility managers to incorporate such a discussion into new building designs and bring in temporary equipment suppliers as part of the design team for consultation prior to finalizing a building design. The architects and structural engineers may be needed for consultation as much as the mechanical, plumbing, fire protection, and electrical engineering. Many engineers who work on critical buildings are used to talking about redundancy in system design but maybe not about temporary HVAC equipment connection points and locations of installation.

Basic action steps for planning temporary HVAC can include (but are not limited to) those noted here.

  1. Planning ahead involves taking time to sit down with one or more temporary HVAC service providers. Identify the equipment in the facility that is most essential to the operation of the facility. In most cases, a full replacement of capacity for the entire building will not be needed; however, depending on the building type and function, full system capacity may be desired.

  2. Determine the base load of the essential HVAC systems (heating, cooling, humidification, ventilation, refrigeration) required for a short-term temporary emergency and how to “load shed” all other areas that are not needed. Have a clear understanding of which loads are truly essential and which are desired and the risks associated with not having each load replaced in temporary situations. Understand the tolerances of the space conditioning during temporary conditions. Temperature and humidity levels may be acceptable outside of the normal range of operation on a short-term basis with minimal risk to the operation, occupants, or materials within the spaces.

  3. Understand and be prepared with whatever temporary structural support may be needed for the temporary equipment to be put in place.

  4. Understand and have a plan to provide the space required for the temporary equipment. Location considerations may need to take into account noise levels for both the occupants of the building and the businesses or residential buildings adjacent to the building being served. If the temporary equipment is of the size needed to remain on a large truck, the location may require a parking lot or other solid surface location.

  5. Understand and have a plan to provide the necessary utilities for the temporary equipment. It is important to have a discussion about the energy sources available. Electrical voltages available, gas or propane, water sources if needed, etc. If the temporary equipment is located inside a facility, the ventilation of the space will need to be considered. This may require additional equipment or it may be part of the base building system if planned ahead of time.

  6. Understand and have in place the method to connect the temporary equipment into the larger building systems, if the intent is to utilize all or part of the building system for the distribution of the temporary HVAC services. In some buildings, it may be possible to strategically install the temporary equipment in locations convenient to isolation dampers or valves and temporary fittings that have been designed into the system for this specific purpose.

  7. Determine if the temporary HVAC can be designed into the facility through redundant systems or if portable equipment is needed.

  8. Determine if the temporary HVAC equipment is to be owned or leased on an as-needed basis.

  9. Have the contact numbers of the temporary equipment readily available and the contract terms already established and agreed upon prior to the need for temporary equipment. Have an alternate source available in case the primary supplier is not able to fulfil the needs of all of their customers.

  10. It may or may not be required, but most likely recommended, that a plan to utilize temporary HVAC equipment be discussed and approved by the local building code authorities so that they are not surprised or put in a situation to shut down the system if it is not considered safe or properly installed and operated. Consult the local code authorities as part of the planning process. Installation of fuel equipment is dictated by codes and industry standards, just as permanent equipment is for safety. Local code authorities will appreciate being a part of the plan and will be able to expedite the process of putting the temporary HVAC equipment in place when the time comes to utilize it.

Heating Options

Depending on the size and capacity of the equipment, one of a variety of heating energy sources may be used. Fossil fuels, electric, hot water, steam, and even solar energy may be possible.

Cooling Options

The cooling sources for temporary equipment could be self-contained DX or tapping into an existing central plant chilled water system if available. Obviously, it would be good to discuss a primary source of cooling and a backup source of cooling in case the primary source is unavailable for some reason. A packaged self-contained cooling unit may be the most convenient, but this may also require more electrical power availability.

Ventilation Air

There may be some short temporary situations where outside air is not provided; however, this is one of the risks to evaluate during planning. There may be an option to provide a greater level of filtration in a recirculating air system, provided that there are ways to monitor the indoor air quality in the space and everyone is aware of the limitations of the system to provide outside air on a long-term basis.


If needed, humidification will require a source of water and possibly chemical treatment depending on the size and capacity of the system. Temporary water trucks may need to be available to provide this source of water if a local water source becomes unavailable.


Some applications may require a higher level of filtration than normal. The temporary HVAC equipment must be designed to accommodate both the clean and loaded filter pressure losses.

Power Sources

Electrical power could come from the main building if there is some way to get the wiring to the equipment location. Another option may be to utilize a temporary emergency generator that would be located near the temporary equipment. As with any fossil fuel fired product, there needs to be a plan for the exhaust to be dispersed safely and a plan to provide sufficient combustion air if the equipment is installed inside of an existing equipment room or temporary shelter.


Temporary HVAC equipment fuel sources may include natural gas, liquid propane, vapor propane, kerosene, and fuel oil. Discuss the merits of assorted fuel type(s) depending on the type of situation where the temporary heating is needed.

By products

The temporary HVAC equipment may or may not have byproduct that needs to be dealt with, such as combustion exhaust piping for fossil fuel fire equipment or condensation drains for cooling coils. The ability to manage the byproducts of temporary equipment will dictate the acceptable locations for the equipment and could cause problems and delays if not considered prior to delivery of the equipment.

Services by Suppliers

Some suppliers of temporary HVAC equipment also have other services available that include load estimating and design of the temporary system, startup assistance, on-site personnel training, periodic site inspections and preventative maintenance, and 24-hour emergency service.

It is essential to have discussions with the suppliers regarding the scope of their services before entering into any type of agreement. Depending on the application, it may be necessary to talk to multiple suppliers to accommodate all the needs of a particular facility. It may also be wise to have contracts with more than one supplier to have a backup source in case the primary source has issues of their own to deal with in a crisis situation.

Resources for Research

You have multiple resources available to begin the process of developing a temporary HVAC plan of action. A few ideas may evolve through internet research, local phone book searching, word-of-mouth referrals from other business owners, local contractors or facility design engineering firms, and of course, product trade shows in the HVAC industry.


 When it comes to providing temporary HVAC for a building, planning ahead is the key to success. Taking time before the need arises to meet with professional consultants, contractors, and suppliers of temporary equipment will allow for optimum implementation and the least amount of downtime. In most large cities, there are resources available to have these discussions fairly readily. In smaller towns or rural areas, it may be necessary to reach out several miles for help.