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Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 1
Electric Infrared Heating Panels
vs. HVAC
- a summary of an U.S. study (1994)
a project report made by
Perl, Germany
October 2016
Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 2
Project report title:
Electric Infrared Heating Panels vs. HVAC
- a summary of an U.S. experimental field study (1994)
Author:
Oswald Oberladstatter, ME
ehaus2020, Perl, Germany
The author has 15+ years of experience working as HVAC-engineer
and project manager for European companies. Since 2011, he engages
in systems-design for "affordable, healthy Net-Zero-Energy-Buildings".
From 2012 until 2015, he organized four European electric infrared
heating industry alliances, and was an expert-member of a German
Standard committee on an European performance testing standard for
electric infrared panels.
Perl, Germany
edition: October 2016
© copyright 2016 by the author
correspondence about this project report should be directed to [email protected]
Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 3
Copyright
Any Third Party may reproduce and / or use this project report in its published form
exclusively for personal and non-commercial purposes without obtaining prior written
permission from the author.
Any Third Party who wants to reproduce, translate and / or use this project report in an
appreviated form or in its entirety in any way or kind for commercial purposes, shall obtain
prior written permission from the author by emailing a Request Permission to
[email protected]. Usually, the author is happy to give written permission, but may
charge a fee.
All rights reserved by the author.
Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 4
Disclaimer
This document has been prepared in good faith on the basis of information available to the
author at the date of publication without any independent verification.
The author and ehaus2020™ do not guarantee or warrant the accuracy, reliability,
completeness or currency of the information in this publication nor its usefulness in
achieving any purpose.
Readers are responsible for assessing the relevance and accuracy of the content of this
publication.
The author and ehaus2020™ will not be liable for any loss, damage, cost or expense
incurred or arising by reason of any person or enterprise using or relying on information in
this publication.
Products may be identified by proprietary or trade names to help readers identify particular
types of products. But this is not, and is not intended to be, an endorsement or
recommendation of any product or manufacturer referred to. Other products may perform
as well or better than those specifically referred to.
More detailed information than has been given about the subject of this publication is not
available.
The subject matter in this project report may have been revisited or may have been wholly
or partially superseded in subsequent work.
For privacy protection purposes, the name, property address and personal identifiable
information was omitted from this publication.
Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 5
Content
1. Abstract ................................................................................. page 6
2. The U.S. study ........................................................................ page 6
3. Facts regarding the three electric heating systems used ........ page 7
4. The research house ................................................................ page 8
5. Heat transfer through walls and windows............................... page 8
6. Heat loss through natural air-infiltration................................. page 9
7. Installed heating system capacity .......................................... page 10
8. Installation of the electric infrared heating system ................ page 10
9. Thermal comfort results ......................................................... page 12
10. Results of energy consumption and operating costs ............... page 15
11. Conclusion .............................................................................. page 16
12. Appendix: 3 major factors ...................................................... page 17
13. Bibliography ........................................................................... page 18
Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 6
Electric Infrared Heating Panels vs. HVAC
- a summary of an U.S. experimental field study (1994)
Author: Mr. Oswald Oberladstatter, ME, ehaus2020, Perl, Germany
Date: April 2015
1 Abstract
Some of the main arguments against surface-mounted electric infrared heating systems
center on the preconceived notions that "all-electric heating is always expensive" and "heat
rises, so placing heating panels up on a wall or on the ceiling makes no sense".
Therefore, the focus of an U.S. study was to compare the thermal comfort, operational
costs and energy consumption in an occupied residential research house for a common air-
to-air heat pump system (HVAC) and a ceiling-mounted electric infrared heating system.
Further, energy consumption was compared to an electric baseboard heating system,
previously installed in the same house.
The U.S. study outcome points towards the fact, that it is more energy-efficient
and thermally more comfortable to heat room-surfaces with surface-mounted
electric infrared heating panels, than by heating the air with an HVAC-system.
2 The U.S. study
Owing to current building standards, European new construction and renovation projects
are highly insulated and air-tight.
In a different direction points a 20+ year old U.S. study /1/. This study provides proof,
that buildings can be energy-efficient and feel comfortably warm inside without extensive
insulation measures, and without an expensive "air-tight thermos bottle" construction.
The study was conducted in 1994 by the National Association of Home Builders (NAHB)
Research Center, a research platform for the U.S. construction industry.
The U.S. Department of Energy as well as the U.S. based company SSHC INC., a
manufacturer of surface-mounted electric infrared heating panels, jointly financed the
research study.
Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 7
The study's main research objectives were:
to use an occupied research house for one-half of the 1993-1994 heating season;
utilizing a data monitoring system to determine the energy-efficiency and
operational costs of surface-mounted electric infrared heaters and an air-to-air
heat pump HVAC-system; operate both systems alternately in 2-week blocks when
possible, otherwise in 1-week blocks;
use data from a previously in the house installed electric baseboard heating
system;
balancing varying weather influences by using a regression analysis of outdoor
temperature and energy consumption, weighted by local weather data.
get feed-back from house occupants regarding thermally discomfortable conditions.
3 Facts regarding the three electric heating systems used
Picture-1 to the left shows a surface-mounted electric infrared
heating panel as used in the study. Panels were each sized
between 0,6 x 0,6 meters to 0,6 x 2,4 meters, featuring a
textured surface coating and an aluminum frame with a 1"
profile. Inside each panel is a solid-state electric heating
element. Even though the regular power supply in U.S.
households is 120V, each panel was connected to 240V. Also
out of the ordinary were hydraulic line thermostats installed
room-by-room. Their advantage was a high accuracy in
picture-1, ©SSHC INC. monitoring the air- and radiant temperatures in the rooms.
Pertaining to the HVAC-system, notable facts are that there were two heat-pump units
installed in the attic, one for the first floor and one for the second floor. The total installed
capacity of the two units was 12 kW. However, since the primary heat source during winter
design conditions is the backup strip-heater with 15 kW of electric power, the total HVAC
capacity under design conditions was 16,7 kW. Very unusual for the 1990's, programmable
thermostats with a "predictive" mode were used, one each installed in the hallways in the
lower and upper floors. This allowed for efficient HVAC operation with setback strategies.
In regards to the electric baseboard system, there are several factors that need to be
mentioned. The installed power for this system was oversized by +54% compared to the
Right-J calculation for the design load of the building. This was standard practice to
anticipate for the day and night setback strategies /2/. This setback strategy in
conjunction with room-by-room thermostatic controls was used in the not-occupied house
to simulate occupancy. Also, the actual indoor temperature was about 1,1°C higher as
compared to the surface-mounted infrared heating system and the HVAC-system.
Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 8
4 The research house
Picture-2 below shows the now disassembled research house which was a fairly typical
American contemporary detached home. It was located on the grounds of the NAHB
Research Center in Bowie, Maryland, close to Washington D.C. on the U.S. East Coast.
picture-2: the AFSD House, © by Jane Willeboordse, Popular Science, Sept. 1990
The house was built in 1990 as a 2-story single-family home with ca. 205 square meters of
floor space and an attached garage. Because of its modular construction, sprinkler system,
etc., the house was called the "Adaptable Fire-Safe Demonstration House" (AFSD House).
5 Heat transfer through walls and windows
Exterior walls were made with a common "2x4" wood frame construction with 2,45 meter
ceiling heights, painted gypsum board on the interior, wood or vinyl siding on the exterior,
and 0,10 meter thick fiberglass insulation batts inside the wood-frame walls.
Casement windows used in the AFSD House consisted of wooden sashes with double
glazing and a crank operator. Typical for U.S.-buildings in the 1990's, the window glass
had no low-e coating and no energy saving inert-gas in the glazing cavity.
The heat transfer value, called "U-value", based on the international Standard ISO 6946
for the wall construction is 0,31 W/m2∙K /3/. The U-value for the windows is estimated
with 2,55 W/m2∙K /4/.
Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 9
In comparison:
The minimum U-values as per the German building code "EnEV2014" for exterior walls are
0,24 W/m2∙K, and for windows 1,30 W/m2∙K /5/. Thereby, U-values of the AFSD House
are considerably higher than the German building code.
However, winter design conditions with an outdoor air temperature lower than -10,5°C in
97,5% of all measurement intervals, make the winter climate conditions of the AFSD
House study comparable to Middle-European locations.
6 Heat loss through natural air-infiltration
Displacement of warm interior air by colder outside air through tiny gaps in the building
envelope is called natural air-infiltration. This is another primary parameter of heat loss in
buildings and closely related to construction materials and methods.
The basic principle:
The higher the natural air-infiltration rate, the higher the heat loss
of the building.
To determine the natural air-infiltration of the AFSD House, a "blower-door test" in
accordance with the ASTM Standard /6/ was performed prior to the start of the research
project. With the air-ducts sealed, as would be the case with infrared heating, the natural
air-infiltration rate for the house was 0,88 per hour. With the air-ducts open, as in the case
for HVAC heating, the air-infiltration rate was 0,99 per hour.
With the air-ducts open, this resulted in a 12,5% higher natural infiltration rate than with
air-ducts sealed. U.S. research indicates, that forced-air heating systems may have an up
to 36% higher natural air-infiltration rate /7/.
A natural air-infiltration rate of 0,88 per hour, as with electric infrared heating in operation,
places the AFSD House in the U.S. "average" category of 0,7 to 0,88 per hour /8/.
In comparison:
A recent Austrian blower-door study /9/ in 3 old and new residences measured air change
rates of 4,8 to 8,3 per hour at 50 pascal pressure differential.
Dividing these rates by 16 /10/results in a natural air-infiltration rate of 0,3 to 0,52 per
hour, averaging 0,4 per hour.
This indicates, that the natural air-infiltration rate of the AFSD House with 0,88 is more
than double that of typical Austrian residences with a 0,4 infiltration rate.
Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 10
7 Installed heating system capacity
For benchmarking purposes, the common U.S. Right-J m method was used to calculate the
building heat load /11/.
Table-1 Right-J
building heat loss calculation
electric
baseboard HVAC
surface-mounted infrared panels
indoor air temp.
outdoor air temp.
21,1 °C
- 10,5 °C
21,1 °C
- 10,5 °C
21,1 °C
- 10,5 °C
18,3 °C
- 12,2 °C
assumed natural
air-infiltration 0,7 0,7 -- 0,4
setback strategies
anticipated no yes yes yes
heating system's
installed capacity 13,3 kW 20,5 kW 16,7 kW 8,1 kW
comparison
100% +54% +26% - 40%
Explanation about table-1:
According to the AFSD House study, almost all of the 40% reduction in installed heating
capacity vs. the Right-J calculation originates from using 0,4 as natural air-infiltration rate.
That is 43% less than the 0,7 assumed rate by the standard Right-J method, and about
55% less than the actual 0,88 natural air-infiltration rate of the AFSD House, but equals
the average natural air-infiltration rate of the Austrian study mentioned above. Different
indoor/outdoor design temperatures accounted only for ca. 4% of the difference in the
calculation results, whereas thermostat setback strategies had no influence.
The AFSD House study results confirmed, that the electric infrared panel
manufacturer's heat loss calculation was correct, providing sufficient thermal
comfort even in cases below winter design conditions.
In comparison: The 40% reduction in installed heating capacity of the surface-mounted
infrared heating panels in the AFSD House compares well to current Middle-European data.
A German study /12/, building project presentations at a German Workshop /13/, and
results from a 1950's German residence /14/, all point to the same fact: a 30% to 60%
reduction in installed heating capacity vs. accepted building standard calculations provide
sufficient thermal comfort to occupants under winter design conditions. However, this does
not apply to buildings with high moisture content in their construction materials, i.e. new
buildings made of regular concrete, or buildings with moisture problems (mold, mildew).
8 Installation of the electric infrared heating system
Picture-3 and -4 on the next page display the floor plans of the AFSD House with the
locations of the ceiling-mounted electric infrared heating panels.
Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 11
picture-3: AFSD House 1st floor, © 2015, 2016 Oswald Oberladstatter
family room bathroom 7,3m2 kitchen
22,11m2 9,05m2
dining room
15,28m2
garage
den / bedroom foyer living room
16,52m2 15,65m2
location of ceiling-mounted electric infrared heating panels
The AFSD House had 205 square
meters of living space and 16 ceiling- picture-4: AFSD House 2nd floor,
mounted electric infrared heating © 2015, 2016 Oswald Oberladstatter
panels with a total heating capacity
of 8100 Watt. This results in an
installed heating capacity of bathroom bathroom bedroom
39,5 Watt per square meter of 6,99m2 6,50m2 11,18m2
living space. Surface temperature
of the infrared heating panels during
operation was between 65,5°C and
ca. 76,5°C. 9,18 square meters of
infrared panel surface was installed
on the first floor, 6,48 square meters master
on the second floor. In total, panel bedroom
surface was 15,66 square meters, 16,52m2 (open) bedroom
equating to infrared heating panel 15,65m2
surface of 8% of the living space
area.
Note: the study mentioned, that for
the 22,11 square meters large family room, the 2,23 square meters of installed infrared
heating panel surface (10% of family room floor space) was probably too little. The likely
reason for that: the room with its 5 exterior room surfaces (3 walls, ceiling, floor), had
more heat loss than the average room with only 2 to 3 exterior room surfaces. The
thermostats setback air temperature was 15,5°C. The AFSD House study also mentions,
that the setforward air temperature of 20°C was probably at the lower margin of
thermal comfort for both house occupants.
Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 12
9 Thermal comfort results
The "operative temperature" is a useful parameter in assessing the thermal comfort of
house occupants. To derive the median operative temperature in a room, globe-sensors
measured the mean radiant temperature and the ambient air temperature in a room.
Based on scientific studies, the following describes the ideal range for the operating
temperature.
During winter conditions, if the operative temperature stays
within 20°C to 24°C in a room, about 90% of room occupants
may feel thermally comfortable /16/.
In the AFSD House, three globe-sensors were located in three different locations to
continuously monitor the operating temperature during the operation of the HVAC- and
surface-mounted infrared heating panels.
The AFSD House was occupied by a working couple. The female house occupant submitted
four times as many thermal discomfort claims as the male occupant. This supports the
notion that women are in general more sensitive to changes in thermal comfort than men.
However, quick changes in temperature seem to have the same effect on women and men.
One such case is "infrared panel cycling" as depicted in picture-5 below.
picture-5: infrared panel cycling and thermal comfort, © 2015, 2016 Oswald Oberladstatter
Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 13
Picture-5 on the previous page displays a sharp drop of the operative temperature within a
20 minute period from about 23°C to 21°C. This was caused by the infrared heating panel
cutting off at 13:35pm and cutting back on again at 13:55pm ("infrared panel cycling").
At that time, occupants were sitting in the dining room right beneath a ceiling-mounted
infrared heating panel. During this "infrared panel cycling", occupants experienced
occasionally thermal discomfort.
Interestingly, at the same time two other occupants in the room who were not located
right beneath the infrared heating panel, did not register thermal discomfort.
Thermal comfort recommendations from the AFSD House study:
In regards to thermal comfort with surface-mounted infrared heating panels,
there is a difference between "rooms" and "open spaces". In connected open
spaces like the area of the dining and living room in the AFSD House, it is better
to connect all infrared heating panels located in this open space to one thermostat,
in order to avoid thermal discomfort for moving-around occupants.
For thermal comfort reasons, the study also suggests that "the square area of
panels installed should be held constant while increasing the number of panels".
In other words: It is better to use more infrared heating panels that are
smaller in size, than just one big panel per room or open space.
In the experience of the author, with surface-mounted electric infrared heating panels keep
the thermostat's setback air temperature at least at 18°C. Contrary to popular belief, in
general this saves energy for heating-up all room surfaces every morning. It also reduces
heat-up time, and therefore improves occupants' thermal comfort.
Furthermore, the AFSD House study noted, that with the surface-mounted infrared heating
panels in operation and occupants having substantial skin surface exposed, the occupants
mentioned on occasion that walking from room to room felt rather cool.
However, AFSD House occupants also felt that acceptable thermal conditions could be
achieved in approximately 10 to 15 minutes if activity was restricted to the proximity of
the surface-mounted infrared heating panels. Establishing thermal comfort in the entire
room required approximately 45 minutes.
This corresponds well with research data from the Pierce Foundation /15/, showing that
occupants of an infrared heated enclosure accept cool spaces upon entry as long as the
infrared heating system can raise the operative temperature within 15 minutes to
acceptable levels.
Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 14
Typical air- and operative temperatures in the dining room of the AFSD House, with winter
outdoor air temperature at around -2,2°C are shown in picture-6 below.
picture-6: typical air- and operative temperatures, © 2015, 2016 Oswald Oberladstatter
In picture-6, the air- and operative temperatures of the HVAC-system are almost the same
and largely between 19°C to 20°C. For the surface-mounted infrared heating system, the
air temperature is ca. 18°C, and the operative temperature ranges from 21,5°C to about
22°C. The operative temperature remains therefore within the previously recommended
operative temperature range of 20°C to 24°C.
These monitoring results confirm a simple fact: Because heat does NOT rise (only
hot air does), it DOES make sense to locate surface-mounted infrared heating
panels up on a wall or on the ceiling.
Even before knowing of its superior energy-efficiency over the HVAC-system, occupants
preferred the surface-mounted infrared heating panels for the following comfort reasons:
occupants had greater control over the heating system on a room-by-room basis,
and therefore more control over their specific thermal comfort requirements;
silent operation of the surface-mounted infrared heating system as there is no air
movement and no fan noise as with the HVAC-system;
occupants had fewer problems with sinus discomfort, especially during the night.
Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 15
10 Results of energy consumption and operating costs
Chart-1 and -2: comparative energy- and cost levels, © Oswald Oberladstatter
Summary of the charts-1 and -2 above:
In regards to the electric infrared heating panels, heating energy consumption was
35,3 kWh per square meter and heating season.
In other words: In the same AFSD House, the surface-mounted electric infrared
heating panels cost about 33% less to operate than the HVAC-system, and 52%
less than electric baseboard heating.
This also refutes the notion that "all-electric heating is always expensive".
The AFSD House study contributes the energy savings from the surface-mounted electric
infrared heating panels to the compounded effect of
reduced parasitic heat losses,
room zoning,
quick recovery from setback, and
heating for comfort.
Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 16
In comparison:
Costs in the chart-2 above are based on the AFSD House study with an electricity price of
$0,055/kWh in 1994 (the currency conversion factor in April 2015 was $1 = €0,88).
For 2015: The residential electricity retail price in March 2015 in Maryland/USA was
$0,1316/kWh (€0,1158/kWh) /17/. The resulting operational costs in 2015 over a heating
season for the surface-mounted infrared heating panels would be $951 (€837), for the
HVAC-system $1.417 (€1.247) and $1.988 (€1.749) for electric baseboard heating.
Pertaining energy-efficiency and sizing of heating systems:
In the professional experience of the author, oversizing a convection-based heating system
by 50% usually leads to very poor energy-efficiency results. This might had been the case
with the electric baseboard heating system which was used for comparison in the AFSD
House study.
The same study also points out, that the undersized surface-mounted electric infrared
heating panels in the family room resulted in occasional thermal discomfort (note by the
author: and probably also poor energy-efficiency, because infrared heating panels are then
almost constantly in operation).
11 Conclusion
The exterior walls and windows of the AFSD House had much higher heat transfer values
and double the natural air-infiltration rate compared to current European building codes.
Despite these facts, the installed surface-mounted electric infrared heating system
enables a superior energy-efficiency and operational cost-efficiency over common
HVAC- and electric baseboard heating systems,
was preferred by the AFSD House occupants for its comfort, convenience and health
features over the air-to-air heat pump HVAC-system,
allows for a 40% reduced heat load capacity as compared to the standard Right-J
heating and cooling load calculation method, and about a 50% reduction based on
the measured natural air-infiltration rate of 0,88 per hour.
The AFSD House study indicates, that energy-efficient and thermally comfortable homes
can be built without ridiculous amounts of insulation and expensive air-tightness
requirements, by using electric surface-mounted infrared panels.
Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 17
12 Appendix: 3 major factors
In the experience of the author, the combination of 3 major factors determines the
energy-efficiency and operations costs for surface-mounted infrared heaters in
residential settings:
1. occupants wants and needs,
2. an understanding on how an infrared heating system really works, and
3. the importance of building materials that match infrared heater characteristics.
Many topics of the 1st factor are well documented in the AFSD House study.
As for the 2nd factor:
The following explains how surface-mounted electric infrared heating panels as main
heating system achieve superior energy-efficiency and thermal comfort in residential
settings:
Surface-mounted electric infrared heating panels work by minimizing
the infrared-heat exchange between humans and room surfaces. Hence,
their main purpose is to elevate the temperatures of all room surfaces.
As an effect, room air temperature can be lower to achieve satisfactory
thermal comfort for occupants.
Pertaining to the 3rd factor:
The thermal characteristics of the interior top-layers of walls, ceilings and floors as well as
furniture surfaces need to be such, as to enable them to act as "re-radiant heaters".
In this regard, there are three basic physical parameters for surface materials:
1. High thermal emissivity of greater than 0,8 in the thermal spectral range
of 2,5 to 50 micrometers, which defines a material's ability to emit infrared
heat. This can be measured with an FTIR-spectrometer;
2. Low thermal effusivity, ideally below 30 kJ/m2∙K, which expresses a
material's capacity about the speed to absorb heat and store it. Effusivity
can be measured by using i.e. a hot disk single-sided sensor device.
3. Fast temperature spread along the surface layer of the material, or as the
author calls it, "blotting-paper effect" (in German: "Löschblatt-Effekt"),
which is important for radiant heat symmetry in rooms. This material
property can be observed by utilizing a suitable infrared camera.
Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 18
13 Bibliography
/1/ Yost, Barbour, Watson for NAHB Research Center, 400 Prince George's Boulevard,
Upper Malboro, MD 20772, U.S.A: An Evaluation of Thermal Comfort and Energy
Consumption for the Enerjoy Radiant Panel Heating System; May 31st 1994
/2/ ASHRAE, 1993 ASHRAE Handbook: Fundamentals, 1993, pp. 25 - 14
/3/ Oswald Oberladstatter, U-value calculation with "U-Therm" software from
German software company Hottgenroth, based on AFSD House wall-construction
/4/ Kennwerte-Fenster (U-values of wood frame windows with double glazing),
page 1, table 1 - Doppelverglasung / Holz-/Kunststoffrahmen, TWW
www.energieberaterkurs.de/export/sites/default/de/Dateien_Kennwerte/
kennwerte_fenster.pdf window U-value
/5/ Minimum U-values as per the current German building Standard EnEV2014
www.enev-online.com/enev_2014_volltext/anlage_03_anforderungen _aenderung
_aU.S.senbauteile _bestand.htm#Anlage 3_Nr_7._Tabelle_Anforderungen
/6/ ASTM Standard E779-87: Method for Determining Air Leakage by Fan
Pressurization
/7/ Palmiter, L. S., I. A. Brown, and T. C. Bond, "Measured Infiltration and
Ventilation in 472 All-electric Homes", ASHRAE Transactions, 91.15.3
/8/ Goldschmidt, V. W. "Average Infiltration Rates in Residences: Comparison of
Electric and Combustion Heating Systems", Measured Air Leakage of Buildings,
ASTM STP 904, H. R. Trechsel and P. L. Lagus, Eds., ASTM, Philadelphia, 1986,
pp. 70-98
/9/ Peter Tappler, Bernhard Damberger, Felix Twdirk, Karl Mitterer, Hans-Peter
Hutter, "Pilotstudie zur Untersuchung des Luftwechsels in Innenräumen für die
Erarbeitung von Vorgaben der Publikation 'Richtlinie zur Bewertung der
Inneraumluft", Endbericht Dezember 2006
/10/ Persily, A. K. "Measurements of Air Infiltration and Airtightness in Passive Solar
Homes", Measured Air Leakage of Buildings, ASTM STP 904, H. R. Trechsler and
P. L. Lagus., Eds., ASTM, Philadelphia, 1986, pp. 46-60
/11/ The Right-J method is a standard design procedure for heating and cooling
systems in the U.S., and certified by the Associated Conditioning Contractors of
America (ACCA)
/12/ Peter Kosack, Report on the Research Project "Case Study of the Differences
between Infrared Heating and Gas Heating in an Old Residential Building, Using
Comparative Measurement", Arbeitskreis Ökologisches Bauen, Technical University
of Kaiserslautern, October 2009
Electric infrared heating panels vs. HVAC, © 2015, 2016 Oswald Oberladstatter Page 19
/13/ Third International Workshop for Infrared Heaters, The correct application of
electric infrared heaters in residential buildings, Technical University of
Kasiserslautern, Germany, April 16th 2015
/14/ Dirk Pulver, electric infrared heaters - a practical point of view, Presentation at the
University of Liege, campus Arlon, Belgium, July 10th 2012
/15/ Berglund L., R. Rascati, and M. L. Markel, "Radiant Heating and Control for
Comfort During Transient Conditions", ASHRAE Transactions, Part 2: 765-775, 1982
/16/ L. Centnerova, J.L.M. Hensen, Energy and indoor temperature consequences of
adaptive thermal comfort standards, Proceedings of the 4th international conference
on indoor climate of buildings, pp. 391-402, Bratislava, 2001
/17/ Average residential retail price for electricity in the USA, March 2015
www.eia.gov/electricity/monthly/epm_table_grapher.cfm?t=epmt_5_6_a