Frequently Asked Questions (FAQ)

Which search criteria should I use?

The default option is 'lowest investment costs'. When searching for lowest investment costs, it will always also search for results and comparible objects which could result into a higher enerylabel. This is not the case for the other three search criteria. An example: starting situation is a house with label "F". When searching for a label "C" finds both "C", "B" and "A" homes. As one of the "B" homes lower investment costs then have the "C" homes, then the "B" homes are delivered as a result.

Do I need to send every feature in the request?

Only the inputs in regard to identifying the object are required. For the calculations the API will fetch the estimated defaults from the database. It is therefore not required to send input for every feature.

Why do I get 0.0 value for Ecovalue as a response?

This could have a few causes:

1. The address is not being recognized when sending "addition": "string". It then interprets ‘string’ as the house number addition.

2. If the current and proposed or desired energylabel are the same, the Ecovalue is zero.

3. An error occurred while calling the API, for example input not according to the schema’s

Why is the Ecovalue a relatively low value?

In combination with other parameters of the object, a small increase in sustainability of the object could result in a label increase from for example E to D and a relatively low market value increase.

Why do I get different results using a budget or maximum investment v.s. using no budget?

When using a budget the default search criterium is flexible (code: 2) in regards to the proposed measures and when there is no maximum investment it uses criterium strict (code: 0). To change this in the search criterium you want be sure to input the desired search options (search_options ) into every relevant API call.

Why don't the different measures add up to the total savings?

To reach the desired energy label, working with a budget or not, it's taken into account that the various measures could have impact when combined. Therefore the total sum of savings per measure isn't always aligned with the advised package of measures.

Why is an object not found?

When the Sustainability API is not able to find an address, or it is lacking the necessary data for the calculations, it will return an error:

Address not found in database, combination of zip code and house number

This can happen for a few reasons:

• The address is not known with the Dutch Land Registry or Municipality

• Critical object data such as the house-type is missing

• The object is not registered as a housing object but instead for example as a farm, industry or shop

How to serve homeowners who want to follow the government's neighborhood-oriented and gasless approach

This can be achieved in multiple ways. The first one being to make an API call where you can get an advice which reduces the usage of natural gas to zero if possible. Add the following to the input:

“natural_gas”: 2,

It is also possible to focus on isolation measures while excluding the heat pump, as this could be facilitated by the municipality in the future. Add the following to the input:

“heat_pump_allowed”: 0,
"lock_measures": {
     "lock": [
       "installation", “shower”, “solar_panels”
     ]
},

How do I cope with an object which has a different energy label than assumed, or where the owner already has taken measures?

It is possible to give different inputs in regard to taken measures. For example if an object already has solar panels or floor insulation. See measures for possible inputs and the page on input on how to structure the API call to get different output and a changed assumed energy label.

The Energylabel used for the sustainability advice is NOT the definitive energylabel known at RVO via EP-online.nl Partly because it could be based on the old norm NEN 7120, but even when it has been established based on the new NTA 8800 norm, it is not possible to know what exactly the situation is in terms of measures.

In order to 'change' the starting point of the sustainability advice, to be similar or as close as possible to the definitive energylabel, it is necessary to input ALL data relevant to the current situation with regard to:

• Surface area

• House-type

• Construction year

• Inhabitants

• Gas usage or city heat usage

• Present solar panels

• Current installation

• Current insulation of the floor, walls and roof

• Current ventilation

• Present shower HRV

Why aren't apartments serviced with this API?

Currently, we don't service apartments in the Sustainability API. For apartment owners, sustainability is organized through the Owners' Association (VVE) as most exteriors are in common ownership. The government provides subsidies for energy advice and energy-saving measures.

Roof, exterior walls, floor (ground floor) and often also window frames are in common ownership in an apartment complex. A decision by the Association of Owners (VVE) is then necessary to improve the insulation of an apartment. It is also often not allowed to install solar panels, solar water heaters or heat pumps without permission.

How does this API cope with the new NTA 8800 norm regarding energy labels?

Altum AI has developed the API regarding sustainability measures and impact based on the NTA 8800 norm.

Why do I get a 400 error response with the message "No housing variant with the selected installation options found with which the goal can be reached within the investment limit. Try again with different inputs and/or different search criteria."?

This usually occurs when performing a request with limitations for either energy label, maximum investment or locking/excluding of measures. Solve by:

• Increasing or removing the feature "max_investment"

• Lowering to "target_label" from f.e. "A" to "C"

• Removing "lock_measures" or "exclude_measure" features used