Analysis of thermal control and heat accounting economic convenience in typical Italian housing unit and climatic zones

In Italy, there are almost 5 million condominium units with central heating and/or domestic hot water and/or cooling systems, where thermal energy is produced by a generator common to multiple apartments or buildings.

Before the entry into force of Legislative Decree 102/2014 [1] and its requirements, only few buildings possessed the possibility to withdraw and pay energy on the basis of actual consumption of individual users, as occurs in case of independent heating; costs were usually divided into fixed rates, proportional to the installed thermal power or to the radiant surface or to the property surface. This situation did not encourage energy savings in any way: for instance, by closing radiators when the house is empty or by improving the walls, windows, floors and roofs insulation. The user’s virtuous behaviour was not refunded by a proportional individual economic benefit.

Temperature control and direct/indirect heat metering for individual apartments systems installation is always a good practice, regardless of the requirements contained in Legislative Decree 102/2014, as amended by Legislative Decree 141/2016 [2]. In fact, the Presidential Decree 412/1993 (art. 7 par. 3) [3] already required that, since July 18, 1991, date of entry into force of Law 10/1991 [4], "new buildings must be designed and built to allow thermoregulation and heat metering for each apartment", and also that "new buildings service thermal plants, whose building permit is issued after June 30, 2000, must be equipped with temperature control and heat accounting system for each housing unit".

Not surprisingly, Law 10/1991 (art. 26, par. 5), in identifying building works subject to technical report, as required by art. 28, provides that "for innovations related to the adoption of the thermoregulation and heat metering systems and for the related allocation of heating costs according to actual consumptions, the condominium assembly decides by majority vote, notwithstanding civil code articles 1120 and 1136". The above provision was amended by Law 220/2012 (art. 28 par. 2) [5], concerning amendment to condominium regulation, by ordering that the condominium assembly decides by the majority provided for article 1120, paragraph 2 of the Civil Code, "the resolutions must always be approved with a number of votes representing the majority of the present people and at least half of the building ownership”.

However, Directive 2012/27/EU [6] and its implementing Italian Legislative Decree 102/2014, set great caution in imposing specific obligations for older buildings and legitimately not equipped with temperature control and heat metering devices. If the plant adjustment interventions are not paid back by related energy savings, e.g. they are not "efficient in terms of costs", they are excluded from the obligation: the evaluation is referred to the cost-benefit analysis methodology, evaluated over the devices lifetime, according to UNI EN 15459 [7] standard.

In point, the Legislative Decree 102/2014 is very clear: if a qualified expert in a technical report states that there is not efficiency in terms of costs, devices installation becomes optional and penalties do not apply. This exclusion joins the economic saving private interest with the public one of reducing energy consumption, so to promote good behaviours, motivated by the awareness to save money or to have a more flexible plant management.

A study published in the 3^rd ANACI-CENSIS Report [8] asserts that the 34.4% of the respondents citizens, interviewed after installing the heat metering systems, has indicated that it has saved nothing, or even to have spent more.

Since building energy need depends directly on insulation level, climatic conditions which affects both transmission and ventilation heat losses, operating time characteristics (e.g. holyday houses in tourist winter or summer places) and plant efficiency, the lower the energy amount demand is, the lower is the related energy and economic saving [9, 10].

In the present paper only the indirect metering system, which is the most common in Italy, and the effect of climatic conditions are considered; the other parameters influence will be taken into account in future researches.

Italy is divided in six climatic zones from A to F on the basis on the heating degree days (HDD), as reported in Table 1. The 2,100 HDD value (upper limit of the D zone) is considered the higher level of the moderate climate: in this condition, the average seasonal (winter) indoor-to-outdoor temperature difference is about 12.6 °C.

Energy efficiency improvement of a building plant located in F climatic zone determines higher annual energy savings compared to the same improvement performed in zone A; in the latter case, the adjustment costs are not easily covered by the related savings owing to lower energy consumption.

Even if no legal obligation is set, temperature control and heat metering devices installation is always to be taken into consideration, since the cost effectiveness is estimated using statistical data and it doesn’t consider any incentives in force. Furthermore, if the user is properly trained about temperature control devices use, real energy and economic savings can be even greater.

In the paper, cost-benefit analysis is carried out on a large scale and on statistical basis in order to demonstrate the economic impact of thermoregulation and heat accounting devices installation, referring to the average Italian housing unit and considering both the presence or the absence of tax-free discount nowadays available. The analysis has been performed through calculation of two indicators: the simple payback period (SP) and the net present value (NPV).

Table 2 shows the estimated costs for temperature control and heat metering devices installation for the average building unit, characterized by 76.8 m² useful area and 4.45 radiators (national average). It is set inside a building with 30 residential units (national average), served by a central heating system.

The calculation takes into account not only initial costs of thermostatic valves and heat cost allocators supplying and installation, but also costs related to the design, supervision, management, administration and to the supplying and installation of a variable speed circulator in the boiler room, VAT included. Operating, maintenance and disposal costs have been also considered, included reading charges to annually compute the costs share among users.

Table 2. Cost evaluation for temperature control and heat metering devices installation for the average building unit

Costs shown in Table 2 were obtained for some items from the Price List Works Plants and Construction 2016 of Liguria Region. The compatibility of these prices with those reported in the ENEA national analysis, reported in [14] and [15], have been checked. For the item "project, work supervision, testing, energy audit, allocation indicators" reference was made to the DM 140/2012 [16]. Maximum useful life of devices and the incidence of maintenance and disposal costs have been deducted from Annex A of UNI EN 15459 [7].

Meters have 10 years lifespan: the shortest among all considered components. In this time span, all costs, inflation effects and residual economic value of life for devices whose useful life is longer than 10 years (pumps and thermostatic valves) have been considered.

All inclusive, the charge cost per building unit is approximately 1,071 €.

In the four years since the publication of the Directive 2012/27/EU and in the two more elapsed since its transposition by the Legislative Decree 102/2014, Italian citizens have not perceived the utility, first of all, to verify by means of a technical evaluation, if the temperature control and heat metering devices installation was or was not efficient in terms of costs.

The present study shows that it is statistically possible that buildings located in warmer climatic zones (typically A, B, C and D) may be not subjected to the imposition of the Legislative Decree 102/2014. The imposition remains for about 50% of the whole national real estate located in colder ones (typically E and F).

In cogency absence, owners could defer the immediate urge and could plan in subsequent years better interventions settled as part of a reasoned and affordable global energy refurbishment. Such behaviour would spread over time interventions and limit the anomaly of the market which, in the indifference of many, we are living in the last two years, with an exceptional concentration of economic interests in a limited period of time and on a few subjects. Indeed, many companies have ridden the inclination of the Italian population to not inquire about the original legislative text purposes and, using some law interpretation, push in the direction "of mandatory adjustment obligation at all costs".

Laws must be read so to satisfy the legislator’s will, and it does not seem reasonable to think that the European Union intends to impose on Italy to adapt some 22 million radiators in two years, or better, in the few summer months when it is possible intervene with the heating systems off.