I think your Ernest is the Earnest Wertz, son of Howard and May Wertz. Take a look:
1920 United States Federal Census about Ernest Weitz
Name: Ernest Weitz [Ernest Wertz]
Home in 1920: Harrison, Bedford, Pennsylvania
Age: 13
Estimated birth year: abt 1907
Birthplace: Pennsylvania
Relation to Head of House: Son
Father's name: Howard Weitz
Father's Birth Place: Pennsylvania
Mother's name: Mae Weitz
Mother's Birth Place: Pennsylvania
Marital Status: Single
Race: White
Sex: Male
Able to read: Yes
Able to Write: Yes
Household Members: Name Age
Howard Weitz 50
Mae Weitz 30
Ernest Weitz 13
Bertha Weitz 4
Source Citation: Year: 1920;Census Place: Harrison, Bedford, Pennsylvania; Roll: T625_1533; Page: 4B; Enumeration District: 14; Image: 363.
Farm on Cove Road, Jan. 14, 1920
Wertz, Howard, head, owns house, 50, b. PA, parents b. PA, laborer for working out,
Mae, wife, 30, b. OH, parents b. PA
Ernest, son, 13, b. PA, parents b. PA,
Bertha, daughter, 4 5?/12, b. PA, parents b. PA,

1910 United States Federal Census about Howard Wertz
Name: Howard Wertz
Age in 1910: 29
Estimated birth year: abt 1881
Birthplace: Pennsylvania
Relation to Head of House: Head
Father's Birth Place: Pennsylvania
Mother's Birth Place: Pennsylvania
Spouse's name: Mary Wertz
Home in 1910: Harrison, Bedford, Pennsylvania
Marital Status: Married
Race: White
Gender: Male
Household Members: Name Age
Howard Wertz 29
Mary Wertz 20
Earnest Wertz 4
Source Citation: Year: 1910; Census Place: Harrison, Bedford, Pennsylvania; Roll: T624_1312; Page: 4A; Enumeration District: 0013; Image: 212; FHL Number: 1375325.
April 21, 1910, Lower Cove Road
Wertz, Howard, head, 29?, married once 3 years, b. PA, parents b. PA, Farmer on home farm,
May, wife, 20, married once 3 years, 1 birth, 1 living, b. PA, parents b. PA,
Earnest, son, 4, b. PA, parents b. PA,

This may be Howard in 1900:
1900 United States Federal Census about Howard Wertz
Name: Howard Wertz
Home in 1900: Harrison, Bedford, Pennsylvania
[Manns Choice, Bedford, Pennsylvania]
Age: 28
Birth Date: Apr 1872
Birthplace: Pennsylvania
Race: White
Gender: Male
Relationship to head-of-house: Head
Father's Birthplace: Pennsylvania
Mother's Birthplace: Pennsylvania
Marital Status: Single
Household Members: Name Age
Howard Wertz 28 Farm Laborer
Source Citation: Year: 1900; Census Place: Harrison, Bedford, Pennsylvania; Roll: T623_1375; Page: 9A; Enumeration District: 14.
June 21, 1900

This may be Howard in 1880:
June 1, 1880
1880 United States Federal Census about Howard Wertz
Name: Howard Wertz
Home in 1880: Harrison, Bedford, Pennsylvania
Age: 10
Estimated birth year: abt 1870
Birthplace: Pennsylvania
Relation to Head of Household: Son
Father's name: Hugh F. Wertz
Father's birthplace: Pennsylvania
Mother's name: Susannah Wertz
Mother's birthplace: Pennsylvania
Occupation: Helps On Farm
Marital Status: Single
Race: White
Gender: Male
Household Members: Name Age
Hugh F. Wertz 53
Susannah Wertz 48
Mary Jane Wertz 25
Calvin Wertz 23
Hugh M. Wertz 20
Howard Wertz 10
Source Citation: Year: 1880; Census Place: Harrison, Bedford, Pennsylvania; Roll: 1098; Family History Film: 1255098; Page: 125B; Enumeration District: 222; Image: 0257.
Wertz, Hugh F., 53, farmer, has hernia,
Susannah, wife, 48, keeping house, has heart disease,
Mary Jane, 23, daughter, without occupation,
Calvin, 23, son, day laborer,
Hugh M., 20, son, helps on farm,
Howard, 10, son, helps on farm,
all b. PA, parents, b. PA

1870 United States Federal Census about Howard Wertz
Name: Howard Wertz
Birth Year: abt 1869
Age in 1870: 8/12
Birthplace: Pennsylvania
Home in 1870: Harrison, Bedford, Pennsylvania
Race: White
Gender: Male
Value of real estate: View image
Post Office: Manns Choice
Household Members: Name Age
Hugh F Wertz 44
Susanah Wertz 38
Mary Jane Wertz 15
Calvin Wertz 13
Hugh Wertz 10
Howard Wertz 8/12
Source Citation: Year: 1870; Census Place: Harrison, Bedford, Pennsylvania; Roll: M593_1304; Page: 461B; Image: 247; Family History Library Film: 552803.
July 12, 1870
house visit 11, family visit 11,
Wertz, Hugh F., 44, farmer, land value 2500, property value 300, b. PA
Susannah, 38, keeps house, b. PA,
Mary Jane, 15, b. PA,
Calvin, 13, b. PA,
Hugh, 10, b. PA,
Howard, 8/12, b. PA,

1860 United States Federal Census about Hugh Wertz
Name: Hugh Wertz
Age in 1860: 30
Birth Year: abt 1830
Home in 1860: Juniata, Bedford, Pennsylvania
Gender: Male
Source Citation: Year: 1860; Census Place: Juniata, Bedford, Pennsylvania; Roll: M653_1072; Page: 264; Image: 272; Family History Library Film: 805072.
June 15, 1860
house visit 288, family visit 288
Hugh Wertz, 30, day laborer,
Susan, 28,
Mary J., 5,
Calvin M., 3,
Uriah, 2/12,
Martha C. Holler, 26,
Wm. W. Holler, 1,
Francis Holler, 3/12,
all b. PA

I didn't find Hugh and Susannah Wertz in 1900 census
I didn't find Hugh in 1850 census