SMHI Forecast Control

Optimize the energy consumption

Forecast Control is a tested method that makes it possible to utilize the heat-storing properties of a building, as well as solar and internal energy, considering upcoming weather.

Forecast Control makes it possible to achieve:

  • Energy saving up to 20 kWh per sqm and year
  • More equable indoor climate
  • Reduced environmental impact

Climate impact and weather

Weather has a major impact on energy demand and comfort in buildings. Heating is not only affected by outdoor temperatures, but also by solar radiation and wind.

In our climate we notice this clearly since temperatures, wind, cloudiness and solar radiation vary depending on each other. Usually winds blow less, the colder it is. At the same time, cold days are often sunny. Mild days however are characterized by cloudy and breezy weather.

These connections explain why the increase rate of the need for heat falls when temperatures fall. This is also the cause of a well-known problem in property management - finding an optimal relation between the need for heat and outdoor temperature.

Turn problems into opportunities

Today property management is governed mainly according to outdoor temperatures. When weather changes, difficulties may easily occur. The thermal inertia of a building is not utilized wisely and it is difficult to maintain the desired indoor temperature.

For example, a changeover from a cold night to a clear and sunny day leads often to over-temperatures indoors. On the other hand when the weather is milder but cloudy and breezy, it becomes easily cold indoors, with complaints from tenants as a result. In such a situation the temperatures are usually ruled up.

However, this reinforces the over-temperature tendency during the return of colder but calm and sunny weather. The consequence is thus constant recurring adjustments of the control curve.

Equivalent temperature

SMHI has developed the ENLOSS energy balance model, which estimates individual buildings' needs for heat or cooling to maintain an equable indoor temperature.

The energy demand is converted into a so-called Equivalent Temperature (Te), which takes account of outdoor temperature, solar radiation and wind, in combination with the specific building’s location, properties and ways of use.

Setting out from local, accurate weather forecasts the building’s future need for heat is then estimated. Then it is possible to customize the energy supply to upcoming weather changes and utilize the thermal inertia of the building. In this way it is possible to achieve an energy consumption that is generally lower and an indoor climate that is generally more equable.

Forecast Control - an intelligent dispatcher

Every day a long-term forecast including hourly temperature equivalent values is sent to the building in question. The forecast is either received directly in the pre-programmed duc of the building, or sent to a forecast receiver, which in turn communicates with the available control centre unit. Then the forecast receiver converts the forecast into a control signal that displaces the set point in the central unit.

The forecast receiver converts the forecast value of Te to a control signal customized to the control central unit.


Several years' experience shows that forecast control makes it possible to reduce the energy consumption by 10-20 kWh per sqm annually while simultaneously improving the indoor climate. The fact that reduced energy consumption also is good for the environment is something that is to the benefit of all.

Forecast Control with SMHI WeatherSync ® is suitable for most types of large buildings such as multi-dwelling blocks, office buildings, homes designed for the elderly, nursing homes and hospitals.

How can I subscribe to the Forecast Control with SMHI WeatherSync®?

In order to subscribe to Forecast Control with SMHI WeatherSync® you should turn directly to our partners.

Our partners are responsible for the technical solution, including forecast receivers and related communications systems together with installation, start up and performance monitoring. Using web-based technology, you as a customer can also monitor your installation via Internet.

The technical systems are customized to the most common control systems on the market, and are easy to install.